Hi. I work at a company that does statistical analytics for insurance companies. I've been following SL4 topics ever since I was 12, when I Asked Jeeves about the meaning of life and got a reasonable answer. I used to be a regular in the #SL4 IRC channel, but very rarely posted to the mailing list. I'm even more of a lurker here.
I wouldn't answer the astrology/UFO question. Extraterrestrials visiting in flying human-vehicle-sized ships from human-visible distances is so horribly anthropomorphic as to make it immeasurably improbable. Both propositions are far less likely than me winning the lottery, and that's the best I can get from my wetware. Anything further is like asking, "Which are you more certain is a European country, France or Spain?"
Also, I'm inclined to avoid questions of this form on principle. It's like Yudkowsky's "blue tentacle" in Technical Explanation: Being able to find outs for a theory that doesn't fit evidence is anti-knowledge, and the more practice you get at it the crazier you become.
Due to a severe birth defect, the baby is profoundly mentally retarded, will suffer severe pain its entire life, and will most likely not live to see its fifth birthday.
Unfortunately, thus phrased it fails as a litmus test. For better discrimination, leave out the part about childhood death, then the pain. Then, if you're adventurous, the retardation.