I noticed that since 0.8, Soylent’s protein comes from a blend of rice and pea isolates. I recall it being mentioned during one of my college courses that it was discovered Tibet had a very low birth rate due to a high consumption of peas. A quick google for “peas fertility” or “peas infertility” (both searches without quotes) will quickly turn up some results. Apparently, there’s a chemical in peas called m-xylohydroquinone which is responsible for the contraceptive effect. Now I have no idea whether m-xylohydroquinone is found in the protein of the pea or elsewhere, but I thought I would raise the issue so your science folks could do the research. It would be pretty bad for sales if Soylent drinkers were found to have lower fertility rates!
EDIT: People are asking for some scientific backup to this claim (which is a completely justified request). Please scroll down to my later post for a snippet from an article I found.