Of course, essentialists argue that everything is somehow determined in utero, by so-called "male" and "female" brains, quoting studies (which they never link to) that were done on very small numbers of people, flawed and without control groups. (What is the control group for gender conditioning? People who were raised without a gender assignment at birth? Don't exist.)

OK, I'm an essentialist. Actually a Feminist Kantian Realist, if you're into categories.

And I did give the links. But many don't, and it's not always feasible. You didn't for example, but I think that's reasonable under the circumstances, and is no criticism.

The really valid criticism you had is the small sample size of all of these studies. The criticism can only be partially ameliorated by pointing to the fact that while n is small, the proportion of the Universal Set is relatively large.

In other words, there are so few TS people that a sample size of only a dozen individuals may in fact be equal to every single one in the immediate area, sampling perfection. The Dutch initial autopsies were on every TS person in the whole country who had died in the previous months.

As for controls, there is one famous example that immediately comes to mind. Or rather, infamous.

From the Intersex Society of North America

http://www.isna.org/faq/reimer

David Reimer was born an identical (non-intersex) twin boy in 1965. At the age of 8 months, David and his brother each had a minor medical problem involving his penis, and a doctor decided to treat the problem with circumcision. The doctor botched the circumcision on David, using an inappropriate method and accidentally burning off virtually all of David’s penis. At the advice of psychologist John Money at Johns Hopkins University, David’s parents agreed to have him “sex reassigned” and made into a girl via surgical, hormonal, and psychological treatments—i.e., via the system Money advocated for intersex children.

For many years, John Money claimed that David (known in the interim as “Brenda”) turned out to be a “real” girl with a female gender identity. Money used this case to bolster his approach to intersex —the approach that is still used throughout much of the U.S. and developed world—one that relies on the assumption that gender identity is all about nurture (upbringing), not nature (inborn traits), and that gender assignment is the key to treating all children with atypical sex anatomies.

As it turns out, Money was lying. He knew Brenda was never happy as a girl, and he knew that as soon as David found out what happened to him, David reassumed the social identity of a boy.

The case of David Reimer has been used by the proponents of the “gender is inborn” (nature) theory as proof that they are right. We like to point out that what the story of David Reimer teaches us most clearly is how much people are harmed by being lied to and treated in inhumane ways. We don’t think we can ever predict, with absolute certainty, what gender identity a person will grow up to have."

See also http://www.cbc.ca/news/background/reimer/ and others

The whole Nature vs Nurture debate is not theoretical to people like me. And some people's non-evidence-based philosophies have had tragic consequences.

David Reimer committed suicide on May 4, 2004. He was 38.

There were other problems in David's life, and the way he was treated may not have been causal. It can hardly have helped though.

A sizeable proportion of the TS people I help on support sites - though not even 10% - are Intersexed people "normalised" to the incorrect gender shortly after birth. I see such cases literally every week. It can't help but affect me, and much as I try to remain objective, I can't be.

See Cosmos Magazine articles on David Reimer, and other case studies (including mine)

http://www.cosmosmagazine.com/node/1462

http://www.cosmosmagazine.com/node/1461

My thanks for your courteous and rational critique. I hope I've answered in the same spirit.