In other words, reducing testosterone alone seems to practically eliminate the male advantage in those sports.

In 2011, Bearden “generated 11 percent more power than she did last month,” Harper told me from Spain, where she was meeting last week on these same issues with an International Olympic Committee advisory group.

Harper, who is a distance runner in track and field, had much the same experience after transitioning from male to female.

“Within nine months of being on testosterone (suppression), I was running 12 percent slower,” she said.

She also performed research on eight runners who underwent hormone treatment in transitioning from male to female. The upshot of the research, published last year: The runners performed about as well compared to other women as they had against other men.

“They were relatively speaking equally competitive in men’s distance running and afterwards in women’s distance running,” Harper said.

None of this is to say the questions have all been answered and we should simply forge ahead. When I asked Harper about whether a man’s muscle mass reduces to the same level after hormone treatment as a female’s, she said: