Good find! However, I see they forgot to mention the fact that there are millions of people alive today who were exposed to high doses of testosterone-blocking drugs during the second and third trimesters of their prenatal development. I wonder if that has anything to do with the high rates of ->-bleeped-<- in recent years?
The majority of sources I've seen place the peak of prenatal testosterone production at 17 weeks after conception, not 15 weeks. However, in normal male development, it's produced throughout the pregnancy from about week 7 onwards, and there's a further surge of T production during the first few month of postnatal life too (after which the testicles go into a dormant state until puberty). Testosterone, not the Y chromosome, is the key factor that determines whether you develop as male or female, as research on animals, and certain medical conditions in human beings (such as AIS and Swyer's Syndrome), show. In the research on Rhesus monkeys, exposure to testosterone during the second half of the pregnancy induced masculinization of the brain, so presumably something similar applies in humans (and maybe we need some T production postnatally as well, because it takes so long for our large, complex brains to complete their development).
That figure of only 1 in 10,000 being trans considerably understates its true prevalence; there's a study Lynn Conway carried out in 2001 showing that at least 1 in 500 natal male US citizens are now living as women.