Executive summary

Fecal Microbiota Transplant (FMT) is a procedure that involves transferring the stool of healthy people to the guts of unhealthy people. The bacteria in the healthy person’s stool helps to rebalance the unhealthy person’s dysbiotic (imbalanced) gut microbiome, making their microbiome healthier, disease-resistant, and more youthful. Think of FMTs as a kind of super probiotic to optimize your gut health!

Since the microbiome affects almost all aspects of human health, functioning, and development, FMTs are a promising treatment for a huge variety of health conditions, including multiple sclerosis, ALS, neurodegenerative diseases like Alzheimer's, autism, chronic fatigue syndrome, long Covid, and many more. FMTs from young donors might even have rejuvenating effects (Forget young blood - you want young poop!...). 

FMTs can easily and safely be done at home without a doctor with fairly little effort - both for the donor and recipient. All the donor needs to do is put the stools in a vacuum zip bag, remove the oxygen, store them in a freezer, and have them picked up at your doorstep by a dry-ice delivery service to the recipient. See chapter "How to FMT" for more details.

FMT treatment could help a huge amount of people, but it’s severely bottlenecked by a lack of proper donors. Donors must not only be free of various diseases and pathogens, but also exceptionally healthy and with excellent microbiomes — something that's alarmingly rare these days. See the chapter "FMT donor criteria" below. You know you have a great microbiome if you fulfill most of the criteria.

For reasons explained below, babies have a much higher chance than adults of being good FMT donors. Babies can be FMT donors from a few months old (since the procedure just involves taking their stool from their diaper), and usually the younger the donor, the better. This is especially true if the parents take extra steps to ensure that the baby has a great microbiome.

More specifically, becoming parents can ensure that there’s a high chance that the young baby will be a great FMT donor by taking the following steps during pregnancy and after birth:

  • 6-12+ months before birth, the pregnant mother starts taking care of her microbiome (probiotics, lifestyle, diet, etc.) to ensure it's as good as possible at the beginning of the child's life and later on.
    • This is important because the microbiome of the mother (and to a lesser but still very important extent, that of the father and other household members) plays a major role in forming the child's microbiome - for better or worse!
    • Starting early with microbiome interventions is advisable since some take several months up to a year for full effect, though big improvements are possible in a much shorter time.
  • Once the baby is born, the parents set the baby up to have a great microbiome with probiotics, lifestyle and diet interventions, exposing them to many microbes, and avoiding certain harms (discussed in more detail below).

Donating your baby’s stool, and taking the extra steps to make sure they end up actually being good donors, is a huge win for everyone involved:

The child benefits: since the microbiome is very stable over time, optimizing your child's microbiome very early in life sets them up perfectly to have a great microbiome for the rest of their life - along with all the accompanying benefits for health, development, and functioning. Much easier to build a perfect microbiome from scratch rather than fixing a suboptimal one later!

People in need of FMTs benefit:  Through FMTs, you can use your child’s healthy stool to improve your own and other’s microbiomes, and thus health, and cure their gut-borne diseases. And while your new-born is still using diapers, collecting stools is way easier!

Parents can make a lot of profit by selling their child's stool for FMTs. There are a few FMT companies that will happily buy all of your child's stools every day for $20-100/stool - which makes up to $36,000/year for very little effort! One company even pays $500 for stools from exceptionally healthy donors.

It's good for the parents' health. If you want to ensure your child ends up being a good donor, you need to improve your own microbiome; obviously, this has the side benefit of also being good for you!

I discuss other benefits below.

On a personal note, I’ve been struggling with microbiome-related severe chronic fatigue for many years. One of my motivations for writing this post is that I'm looking for FMT donors for myself to treat my severe chronic health issues. I'm hoping that this post motivates a few parents to take care of their child's microbiome and offer their stool for FMTs for me and others.

Find sources, links to papers, etc. for everything discussed in this post in the last chapter.

The following chapters provide more details on various aspects of this topic. They can all be read independently.

My offer to soon-to-be parents

I’ve been struggling with microbiome-related chronic fatigue for many years, and I’m looking for FMT donors myself. That’s why I make becoming parents the following offer: 

If your microbiome and general health is already decent (see chapter below), and if you are willing to take various steps to improve your and your baby's microbiome, then I will help you with my time, money, microbiome coaching, or anything else you’d find helpful, to make sure your child ends up being a good donor.

I’ll also pre-commit to buying at least 300 stools from your baby for $20 each in the first 2 years of its life - assuming (as is likely) that the baby actually ends up being a good donor. 

Obviously, I'd prefer to not pay for the stools. This is just meant as an optional additional motivation for you. Also, I'm happy with any amount of stool. Even just one is great. 10 are much better. Ideally, I'd get ~10 stools picked up once per month over 6-12 months. Additional stools yield diminishing returns and I'd probably pass on some of them to one of the many others in dire need of FMTs - including my dad who needs them for healthy aging (see below)!

This is extremely important to me, so I’m willing to invest a lot. Please PM me if you’re interested.

How to FMT

FMTs can easily and safely be done at home, both for the stool donor and the recipient. Here's roughly how:

  • Find a good donor who is exceptionally healthy and has a great microbiome (see chapter below, or criteria), and screen them thoroughly for various diseases and pathogens.
  • Once you have a donor, they need to put their fresh stools in a vacuum zipper bag, remove the air (oxygen kills most good bacteria in stool), and store them in a freezer.
  • The FMT recipient picks up the frozen stools, or a dry-ice shipping service is used for pickup and delivery.
  • The recipient either puts the stools into capsules to take orally, and/or prepares enemas with the stools for rectal use.
  • Just one FMT from one stool is already great, but for many health conditions multiple FMTs from many stools over several weeks and months are needed.

Reasons to get FMTs

FMTs can help with a very wide range of chronic and acute health conditions

Including Alzheimer's, Parkinson's disease, chronic fatigue syndrome, multiple sclerosis, autism, and many more, as well as of course most gut health issues and allergies.

optimize physical functioning & health

Even if you don’t have any specific health conditions, FMTs can function as a biohacking tool to improve your gut health and thus your mood, energy, sleep, cognitive functioning, immune system, skin, etc. A healthy gut microbiome has been shown to positively impact and regulate virtually every aspect of human health, development, and function.

Healthy Aging & rejuvenation

Forget young blood - you want young poop! The gut microbiome changes with age in characteristic ways. Microbial species that provoke chronic inflammation or otherwise deliver harmful metabolites into the body increase in number. Species that deliver beneficial metabolites, such as the butyrate that is known to upregulate BDNF expression and improve neurogenesis, decline in number. FMTs from young donors have been shown in mice to reverse these changes in a lasting way and rejuvenate various aspects of health, and very plausibly FMTs also do so in humans. See my blog post (DIY) FMT for Anti-Aging & Biohacking.

Restoring your microbiome after taking antibiotics.  

Antibiotics wreak havoc on your microbiome, causing long lasting and likely even irreversible damage by causing dysbiosis and sometimes fully eradicating beneficial bacterial strains. The currently available options to prevent this are likely inadequate, but FMTs do work and are thus highly recommended. As a tip, you might want to freeze some of your own stool before having to take antibiotics - to have them for autologous FMTs to restore your microbiome afterwards.

Why FMTs are a great opportunity for (soon-to-be) parents

The big bottleneck for FMTs is finding young and healthy donors. Only extremely few people in the western world have a good enough microbiome and general health to qualify as a good donor. Healthy stool is very rare and thus precious!

But for reasons explained below, young infants have a much higher chance of being good donors, especially if parents plan for this from the start and take active measures to improve the newborn’s gut health.

Also, children can already be FMT donors at the age of just a few months. There is no known age-limit.

Therefore, there is a great opportunity for soon-to-be-parents to relieve the FMT donor bottleneck by donating their newborn children’s stools. This is a huge win for everyone involved.

Advantages of setting your child up as good FMT donor

Parents taking extra steps for their child to become a good FMT donor is actually a triple-win situation. The parents, the child, and FMT recipients all greatly benefit:

Benefits for the child 

The beginning of a baby’s life is a crucial period in the formation of its microbiome, and a great microbiome is essential for the best possible development of the baby.

The microbiome tends to be very stable over time (barring big disruptions like antibiotics), so getting your child's microbiome right from the very beginning sets them up perfectly for a great microbiome later in life - along with all the benefits that brings for health, development, and functioning.

On the other hand, once a microbiome is out of balance, it is very hard to fix it, which puts your child at higher risk for various diseases later in life. Even if you don’t care about FMT at all, you might want to double down on your child’s gut health for this reason alone.

Benefits for people in need of FMTs. 

This is the main point of this post. If your child is a great FMT donor, you have a great altruistic opportunity to use its stool to improve others microbiome, and thus health. And while your new-born is still using diapers, collecting stools is way easier.

Parents can make a lot of profit by selling their child's stool for FMTs. 

The FMT company Human Microbes pays $500 per stool from a very high-quality donor. See my other post: Being a donor for Fecal Microbiota Transplants (FMT): Do good & earn easy money (up to 180k/y)! Human Microbes has extremely high standards, but selling all of your child's stools every day for $20-100/stool is totally realistic. That'd be $36,000/year for very little effort! Here’s a list of FMT companies.

It's good for the parents' health. 

One of the most important ways to improve your child's microbiome is actually to improve the mother's microbiome (and to a smaller degree the father’s and other household members) since that strongly influences the child's microbiome - for better or worse! We also share a lot of our microbiomes with the people closest to us - especially with other household members. Thus, a healthy child's microbiome also benefits the parents and siblings.

Preserve the option for later.

Even if you (the parent) have no current interest in FMTs for yourself or others, it's wise to at least preserve this option for later, given that it’s great for your child anyway. One day you might become sick with some gut-borne disease, or you may need to take antibiotics which totally mess up your microbiome. It could be handy at that point to have a child who is a suitable FMT donor..  You also might want stools from your much younger child for their anti-aging benefits when you get older. See here.

Why do infants have an especially high chance of being good FMT donors?

  • With infants, you can do everything right from the start. Infants start with a blank state. Their intestines are literally sterile at birth! You can literally end up with a person who has never eaten unhealthy junk food, never done anything harmful for the microbiome (like taking antibiotics) and who has always eaten a perfect diet (breast milk and healthy food later on). It’s much easier to build up a perfect microbiome from scratch rather than having to fix an existing one.
  • With infants, there has been less time for microbiome-detrimental events to occur.
    • There’s a lower chance that they’ve already been infected by any parasites and other pathogens that often stay for life and would exclude someone as a donor. Asymptomatic parasite infections, e.g. by B. Hominis, are very common even in the western world, and not easy to get rid of.
    • There’s a lower chance that they’ve had to take antibiotics.
  • Parents can avoid doing harmful things that usually set one up to not be a good donor. This includes:
    • C-section birth. At the very least do a very thorough "vaginal swab/seeding". See sources at the end.
    • Not breastfeeding for long enough. Not sure how long is best, but I believe the longer the better.
    • Keeping their home environment too sterile, with very little microbe exposure. Exposure to different sorts of microbes is beneficial for the microbiome.
  • The microbiome gets worse as we age. You generally want your FMT donor to be as young as possible, which makes infants an obvious choice.
  • However, infants don’t fully start as a blank state. That’s because one of the most important determinants for an infant's gut health is the gut health of the parents, particularly the mother.
    • This post is mostly/especially relevant for relatively young healthy people who intend to give birth (or have very young children) and who already have a fairly good microbiome themselves. See chapter “FMT donor criteria” below.
    • This is also why the title of this post says soon-to-be parents. Ideally, the expecting parents, especially the mother, start to improve their own microbiome at least 6 months (12 is better) prior to birth through various lifestyle, diet, and other interventions as part of their prepare-for-the-baby regimen. This ideally includes doing FMT from a good donor themselves.
    • Again, parents will likely want to improve their child’s health anyway, regardless of any FMT considerations.

How to ensure a great microbiome for the baby?

  • Note: I’m not an expert on this, so best do your own research. See next chapter for good places to start. Here’s just what I’ve gathered so far.
  • By far the most important determinant for a child’s microbiome is the one of the mother. Focusing on the mother’s microbiome is therefore key.
  • The father’s (and other household members, e.g. siblings) microbiome also has a significant impact and focusing on their microbiome is also a great idea.
  • Improving your microbiome all the way to “perfect” is not easy, since most ordinary interventions only take you so far. FMT is probably the most powerful gut health intervention. That’s why it might be a good idea for the mother to get FMT from a high quality donor herself prior to conception. Buy/get high quality stools once in order to get much more later!
  • Consider not doing a c-section, or at least do vaginal swab/seeding. A newborn needs to be covered in the mother’s microbes and that doesn’t happen during c-section.
  • Try to avoid antibiotics as much as you can, also as a parent. As a parent you really don’t want to mess up your microbiome just as you are passing it on to your child! This alone might be a good reason against c-section, since that one often forces the mother to take antibiotics.
  • Breastfeed for as long as possible.
  • Don’t let the baby grow up in a too sterile environment with very little microbe exposure. Having pets, playing outside in nature, growing up on a farm, etc. are great!
  • There are a few better-researched recommendable probiotics for the baby and mother, e.g. evivo's B. Infantis or Biogaia’s ProTectis. If you don't want to risk giving them to the baby, take them yourself, and you'll pass them on to your baby naturally.
  • Of course, various lifestyle and other interventions are also highly recommended, both for the mother, other household members, and the child. Here’s just a small list:
    • Eat a healthy, diverse (to feed many different bacteria) diet high in fruits, vegetables, nuts & seeds, mushrooms, whole foods & grains, legumes & pulses, etc. 
      Make sure to eat lots of  fibres and phytonutrients. Consider supplementing these.
    • eat fermented foods regularly
    • avoid overly sugary stuff and junk food. I'm also advising against liquid meal replacements like Soylet, Huel, or Queal. Here's why.
    • exercise regularly
    • avoid stress & prioritize mental wellbeing.
    • avoid environmental pollutants, including microplastics, aggressive dishwashers, emulsifiers in food
    • good sleep hygiene
    • intermittent fasting
    • don’t eat 4 hours before going to sleep
    • supplement with butyrate, polyphenols, and multiple different fibers.
    • etc.
  • Here is my google doc with more info: Improving gut health

Further comments, FAQ, etc.

FMT donor criteria

Here is my google doc of FMT donor criteria. You know you have a fantastic microbiome if you fulfil most of the criteria. The gist of it is:

  • very good digestion & excellent poop almost always consistently for at least a few years, i.e. your poop is regular about once per day, of normal brown-ish colour, & fairly  firm and dry, not mushy. A solid "type 3 or maybe 4" on the Bristol scale. This is the most important requirement.
  • incredibly healthy: No chronic illnesses, no allergies, no hay fever or anything like that, good skin, good oral health, rarely ever being sick. Nothing that hints at a suboptimal immune system.
  • Rarely ever do you have gut health issues like bloating, acid reflux, stomach pain, etc.
  • No food intolerances. You can eat everything without any problems.
  • lots of physical and mental energy, ideally athletic and with good mental health. You are usually "bursting with energy". You actually feel fit and healthy.
  • healthy lifestyle: healthy diverse diet, exercising, good sleep, not usually stressed, etc.
  • as young as possible: under 30, ideally even between 0.5-18.
  • no antibiotic use for many years. Ideally never.

Level of evidence & epistemic status

A lot in this blog post doesn't have clear evidence yet. There's just too much about the microbiome we don't yet know. I’m also by no means an expert on any of this. If you plan to do this, I strongly encourage you to do your own research. I’m happy to help you and discuss everything with you along the way.

The following all don't have a clear scientific consensus: Donor criteria, efficacy of FMT, babies as FMT donors, and many of the suggestions to improve a microbiome.

Most of my donor criteria are taken from various (conversations with) FMT companies, blog posts, podcasts, and just my intuitions. There is no scientific consensus on donor criteria other than making sure they don't have any pathogens. Many of these criteria I've simply chosen because they correlate with a good microbiome. I've also taken a "better safe than sorry" approach.

As to efficacy for FMTs: Except for very few conditions, there is no scientific consensus. Many studies actually have very poor outcomes! Here's my write-up of why I am still excited about FMTs.

The whole idea of babies as good FMT donors - and preparing for this in advance for this - is pretty much just my idea, based on my intuition on reading a lot about microbiome. I'm not aware of children under 18 ever being used as FMT donors.

Also, many of my suggestions to improve a microbiome are only based on common sense, educated guesses, anecdotal evidence of “stuff that just works”, and similar. There is a lot of “not (yet?) proven to work, but also not disproven” stuff from alternative health practitioners - and in my experience those are the things that have helped me the most.

The one thing where I do feel very confident about is that the human microbiome is very important for almost all aspects of human health, functioning, and development, and that taking care of your baby's microbiome (including by taking care of your own) is a fantastic thing to do for your baby regardless of any FMT considerations.

Will FMTs cure my own health problems?

I don’t know. I’m not looking for a silver bullet. I’m just doing everything I can that has a chance of improving my microbiome. I think it’s very likely that it will have multiple positive effects on my microbiome, but it also likely won’t cure me completely. I’ll combine FMTs with many other gut interventions and hope for a combined synergistic effect.

Will this cure me?

How confident am I that babies of collaborating parents will end up good donors? And by extension, if selling your baby's poop is your intention, how confident can you be that the “investment” and your and your baby’s microbiome pays off? Again, I don't know. No studies etc. on this. Not even anecdotes. I just feel like it's very plausible!

Reasons for this to fail are:

  • Despite best efforts, the baby (or mother) has to take antibiotics. I don't know for sure how bad antibiotics really are, but they seem pretty bad.
  • The baby might get some (potentially asymptomatic, as often happens) parasite or other pathogen that excludes them as a donor.
  • In the most common case that the parents don't already start with a great microbiome, it's not clear to me how much all the interventions suggested to improve their microbiome prior to birth will work. Fixing a suboptimal microbiome just seems really hard!

Why such strict donor criteria?

Wouldn’t a “merely better than that of the recipient” microbiome already be an improvement? Why the focus on perfection? The answer is complicated. The very short incomplete version is:

  • There is a so-called super donor phenomenon. There seems to be a certain threshold, or certain microbiome features, that once reached make a FMT donor especially effective. The relationship between how good someone's microbiome is and how good they are as a donor doesn't seem to be perfectly linear.
  • Someone with a fairly good but less-than perfect microbiome might still have a few bad bacteria that the recipient not yet has. That might be fine for the donor, but not for the recipient. There is more harm to be done by adding bad bacteria then good by adding good bacteria. Maybe some donor has only one bad bacterial strain that is easily kept at bay by his otherwise stable healthy microbiome. That strain could still cause a lot of problems in the recipients disbalanced microphone.
  • Better safe than sorry. Also, I'm just a microbiome perfectionist!

How much effort & time investment is needed for the parents?

A bit hard to say. Here's what the parents need to do:
Collect the stools. Take the stools from the diaper, put them in a vacuum zipper bag, remove the air, and store them in a freezer. Freezer storage place might be an issue. I'm happy to buy you a small extra freezer for this. I'll also order the zipper bags, etc. and have them delivered directly to your door, and I'll set up a dry ice delivery service to pick up the stools.

Implement the changes that lead to a great microbiome for the parents and child.
Depending on how good your microbiome, diet, and lifestyle already are, there might not be much or even anything to be done. There's no special microbiome diet you and the baby need to be on - just the  general common-sense healthy way of living and caring for the baby that you'd probably want to follow anyway. Also, you don't need to implement everything and nothing needs to be perfect here. And I'm happy to assist you in any way possible to implement healthy lifestyle changes. E.g. I can order probiotics etc. for you.

(Not) doing c-section? I have to do some more research on how important that really is. It might be just fine as long as antibiotics are avoided and a vaginal swap/seeding is done afterwards. In general, there's a lot I also still have to learn about how best to take care of a baby's microbiome. I'm unsure about the importance/usefulness of probiotics, for example. This is a journey of learning we can go on together! 

Communication with me. The whole process involves a bit of coordination and discussion with me. We'll probably have a few video calls about this. For example, I'd like to go through the list of donor criteria with you, ask a bit about your lifestyle, and discuss the microbiome interventions that you feel comfortable with.

Screening for pathogens & parasites of the baby. I have to do some more research on this myself. Probably the baby needs to do a stool test (can be ordered on amazon) to confirm donor suitability. 

sources, science, further links to learn more

books, podcasts, blogs, websites

harms of antibiotics

microbiome interventions for infants

importance of microbiome



Some quotes I came across:

  • "“Like mother, like daughter.” The phrase is often invoked to describe how children resemble their parents. While we know that human genes are passed from generation to generation, an expanding body of research now shows that many microbiome populations are also inherited. The microbes a child inherits are acquired from both parents and even siblings. However, microbial populations inherited from the mother have a particularly strong impact on a child’s development and health."
  • "The impact of inherited microbes cannot be underestimated."
  • "While the vaginal microbiome has received a great deal of attention from the research community, recent research also indicates that microbes persist in the womb, where they come in contact with a fetus before it is born."
  • "Dysregulation of this placental microbiome by pathogens has also been associated with preterm birth and low infant birth weight."
  • "After birth, an infant’s health is further shaped by microbes it continually acquires from its mother’s breast milk. While just a few years ago breast milk was believed to be sterile, it is now understood to deliver a robust microbiome that varies among women. An enteric-breast circulation allows microbes from a mother’s gut to reach her mammary glands and vice versa via the blood. The intensity of this circulatory pathway appears to increase during the end stages of pregnancy and during breastfeeding. Microbes originating in a mother’s intestines may subsequently be present in her breast milk. These microbes may in turn play a large role in forming her infant’s early gut communities."

Help me!

I’ve been struggling with microbiome-related severe chronic fatigue for many years. That’s why one of my key motivations for this post is that I'm looking for FMT donors for myself to treat my severe chronic health issues.

  • I'm hoping that this post motivates a few parents to take care of their child's microbiome and make them available as FMT donor for me and others.
  • I'm also interested in founding a FMT startup connecting good FMT donors with people in need of FMTs.

My offer to soon-to-be parents is:

  • If your microbiome & general health is already decently good from the start,
  • and if you are willing to take the various steps to improve your and your baby's microbiome,
  • then I will help you with my time, money, microbiome coaching, anything helpful, etc. as much as I can with everything involved to make sure your child ends up being a good donor,
  • and I will pre-commit to buying at least 300 stools from your baby for 20$ each in the first 2 years of its life - assuming the likely case that the baby actually ends up being a good donor.
  • This is extremely important to me, so I’m willing to invest a lot! Please PM me.
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For some reason it feels like you wrote everything twice. For example...

I’ll also pre-commit to buying at least 200 stools from your baby for $20 each in the first 2 years of its life - assuming (as is likely) that the baby actually ends up being a good donor.

and I will pre-commit to buying at least 300 stools from your baby for 20$ each in the first 2 years of its life - assuming the likely case that the baby actually ends up being a good donor.

...and there were more examples like that.

Good luck, I hope someone takes this generous offer, because it really seems like free money. But you would probably find more people with babies and needing an extra income at some other community.