This is an issue I've been looking into and reading about for some time now. I've learned quite a bit along the way, including the fact that I still have much to learn about transgender issues and various medical approaches. Regarding sports, the main thing to keep in mind is that women's sports were created for a reason....to provide women athletes space to play and compete. IOW, women's sports are
protective, which means it's important to maintain that protection.
Another thing to keep in mind is that professional sports leagues like the NBA, NFL, PGA Tour, NHL, etc. are not "men's only". They are open to
anyone who is good enough to play in them. The reason they are all male is because there aren't any women good enough to play in those leagues. Some women have tried, but have basically failed.
The NCAA currently has the following guidelines for transgender athletes....
1. A trans male (FTM) student-athlete who has received a medical exception for treatment with testosterone for diagnosed Gender Identity Disorder or gender dysphoria and/or Transsexualism, for purposes of NCAA competition may compete on a men’s team, but is no longer eligible to compete on a women’s team without changing that team status to a mixed team.
2. A trans female (MTF) student-athlete being treated with testosterone suppression medication for Gender Identity Disorder or gender dysphoria and/or Transsexualism, for the purposes of NCAA competition may continue to compete on a men’s team but may not compete on a women’s team without changing it to a mixed team status until completing one calendar year of testosterone suppression treatment.
That seems reasonable to me, and I've shown this to a few transgender folks (online) and they agreed. So I think it would be reasonable for high schools to adopt the same policy for competitive sports. Pre-high school sports should generally be open to anyone, as the biological differences between the sexes hasn't fully kicked in.
The only issue I've seen with this approach is that it potentially excludes transgender athletes who can't afford the type of medical care required by the policy. I agree that's a problem, but I think it's a bigger problem of economics, access to health care in the US, and income inequality, which isn't going to be solved via athletics regulations.
So overall, it seems there's an obvious and fairly simple solution to this, and given the rarity of actual conflicts in the first place, there seems to be only one reason why it's not being widely implemented....conservative Christians have made transgenders their latest group of "others" that they hate on and seek to oppress. They lost the battle over gays, gay marriage, and gay rights, so now they're focusing all that hate on transgenders.