However, finding a difference in the brain is not always evidence for a cause. The brain is not as static as our brain to computer analogies sometimes suggest. There is only one point I would like to add. Marc Breedlove did not address this point because the intended audience of the article is skilled in statistics. A common argument against the findings is the few number of participants.
Many people seem to think that the small numbers mean it's easier to get the findings by a fluke.
Though I would agree replicating the results would make the findings more convincing, the small sample size is not a problem. Otherwise we say the groups are the same. But lower p values make that less likely. Male to female transsexuals have smaller BSTc regions than both heterosexual and homosexual men. The theoretical reasons BSTc was proposed as a possible TS difference imply we would find similar results for transsexual men.