When people compete in boxing rings and in wrestling matches (at least in the high end high class championships) they do so within weight classes (such as feather weight versus heavy weight). Thus to some degree the professional athletes in those events have about the same amount of muscle mass and of body fat.
Furthermore, I am not saying that transgender people should be allowed to compete in women's sports, or in men's sports, instead of only in transgender sports or in integrated sex sport teams (teams which include both men and women). I am indifferent about that, as long as the transgender people have rights equal to non-transgender people. Part of the reason why I am indifferent might be because I have very little interest in sports. I am not an athlete, I have haven't participated in sports at all in over 20 years, I haven't watched sports on TV in more than 25 years (except for rare snippets), and I haven't attended a sports event in over 30 years. [Note: I also didn't watch the video in the first post of this topic thread, other looking a few frames of the video.] I am interested in intellectual matters instead.
In a place I worked in as a temp, all of the workers were required by the boss (a highly progressive person) to accept the sex/gender that all of the workers identified themselves to be. There was one person there who to me looked mostly like a man but as transgender and he wore dresses and identified as a woman. We were instructed to refer to that person as "she" and "her" instead of as "he" and "him", in order to not hurt the person's feelings and probably to avoid being considered guilty of sexual harassment.
At my local library there was a reference librarian who looked completely like a woman (though with short hair) and who I thus definitely thought was a woman, but the person wore a label which said something like "I identify as she and her". Because of the label I presume the person was transgender, but if it wasn't for the label I would never had thought the person was transgender. The person's voice was also completely feminine.
I thus consider what is called a sex change to actually be a sex change, if the process is complete enough.
Regarding how many sexes exist in humans, Matthew 19:12 quotes Jesus as saying some people are born as eunuchs, so most likely a significant number of people were born as eunuchs in the first century CE. Furthermore, the latter part of that verse (in the KJV) says "... and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven's sake. He that is able to receive it, let him receive it." Thus the book of Matthew says Jesus Christ approves of the latter kind of eunuchs.
Isaiah 56:3-4 (KJV) says the following.
"3 Neither let the son of the stranger, that hath joined himself to the Lord, speak, saying, The Lord hath utterly separated me from his people: neither let the eunuch say, Behold, I am a dry tree.
4 For thus saith the Lord unto the eunuchs that keep my sabbaths, and choose the things that please me, and take hold of my covenant;". Thus even according to those OT verses Yahweh approves of eunuchs who faithfully keep his commandments and worship him.
These NT and OT verses thus express a socially liberal theological attitude towards believing eunuchs - namely to believing transgender (of a certain kind) people. Also there is the account in the books of Acts of an Ethiopian eunuch of high authority who quickly became a Christian after learning of Jesus (see Acts 8:27) - but he was not likely born as a eunuch (since he was a government official and and since back then some governments made some of their men into eunuchs).
Regarding how many genders officially exist as a legal status, "On June 15, 2017, Oregon became the first state in the U.S. to announce it will allow a non-binary "X" gender marker on state IDs and driver's licenses. The law took effect July 1. No doctor's note is required for the change.[79] " See https://en.wikipedia.org/wiki/Transgender_rights_in_the_United_States . That same article also says the following.
"Third genders have traditionally been acknowledged in a number of Native American cultures as "two spirit" people, in traditional Hawaiian culture as the māhū, and as the fa'afafine in American Samoa.[68][69][70][71] Similarly, immigrants from traditional cultures that acknowledge a third gender would benefit from such a reform, including the muxe gender in southern Mexico and the hijra of south Asian cultures.[72][73][74] "
Anony Mous, regarding women beating men in tennis, what about Billie Jean King? When I was a pre-teen I learned of her victory over a former No. 1 ranked men’s player. I was deeply impressed by her victory. That victory was a news sensation and a victory for the feminist movement and greatly contributed to me developing progressive beliefs - beliefs based upon evidence. See https://www.history.com/this-day-in-history/king-triumphs-in-battle-of-sexes . It says the following.
"On September 20, 1973, in a highly publicized “Battle of the Sexes” tennis match, top women’s player Billie Jean King, 29, beats Bobby Riggs, 55, a former No. 1 ranked men’s player. Riggs (1918-1995), a self-proclaimed male chauvinist, had boasted that women were inferior, that they couldn’t handle the pressure of the game and that even at his age he could beat any female player. The match was a huge media event, witnessed in person by over 30,000 spectators at the Houston Astrodome and by another 50 million TV viewers worldwide. King made a Cleopatra-style entrance on a gold litter carried by men dressed as ancient slaves, while Riggs arrived in a rickshaw pulled by female models. Legendary sportscaster Howard Cosell called the match, in which King beat Riggs 6-4, 6-3, 6-3. King’s achievement not only helped legitimize women’s professional tennis and female athletes, but it was seen as a victory for women’s rights in general."
Do you say she won because the man was 25 to 26 years older than her?
In my memory of the video news footage that I saw as a pre-teen the man who lost was deeply embarrassed that he lost.