Before I begin, I need to be clear about the terminology I'm about to use.
When talking about how a person sees themselves, what a person considers to be their identity, how a person interacts with other people and expresses themselves socially and artistically, I'll use the word 'gender'. Some people believe that there are 31 different genders identities (and I think this is recognised in law in New York).
When talking about a person's body, in particular their genitals, their skeletal structure, their muscles, their voice, their body hair, I'll use the word 'gexder'. (Yes this is a new word that I made up myself because I find the word 'sex' to be too ambiguous).
When I say 'male', I'm talking in terms of gexder. (penis, sperm, narrow hips, 5'8", hairy skin, big muscles).
When I say 'female', I'm talking in terms of gexder. (vagina, eggs, wide hips, 5'4", smooth skin, small muscles, can become pregnant and give birth to a baby).
When I say 'intersex', I'm talking in terms of gexder (for example a vagina with testicles instead of ovaries, or a penis with ovaries)
And so here is the stance I'm taking:
* When it comes to sport, gender doesn't matter (or at least it should not matter if we treat each other fairly and equally).
* When it comes to sport, gexder does matter because males are taller, faster and stronger. Females would quickly lose interest in competing if they were always pitted against taller stronger faster males.
For the past while I've been seeing snippets on YouTube about transgender people in sport. I think this is a good thing -- I think anyone should feel free to participate in sport and to feel accepted. However I didn't realise that they were letting males compete in female-only events. In some sports, a male only has to prove that their testosterone blood level has been consistently below 10 nanomoles per litre for the past 365 days. Let's forget about their height and bone structure. They're also allowed to have a penis (i.e. no need for gender reaffirmation surgery).
I'm all for equality and equal opportunities for everyone, and I think we should accept people for who they are rather than present them with a list of demands of how they should fulfil our expectations, however I don't think that this means that a 38-year-old man can run in a race for 7 - 9 year olds. I don't think that a person who has the use of their legs can swim in a competition for paraplegics.
If I was going to suggest any kind of change to the Male and Female distinction in sports, then I'd say have two categories as follows:
(1) Gexder restricted to females
(2) Gexder unrestricted
So if a female transitions to male then let them compete in the unrestricted gexder category (because no male is going to complain about a transfemale having an unfair advantage).
But don't allow a male who transitions to female to compete in the female-only competition -- that's just not fair and it will result in people losing interest in spectating on and competing in female-only sporting events.