Weirfan as I asked above , what is your source to back up that claim ?
abnormal is a broad term that can be applied to anyone who isn't average
It seems you're being intentionally confrontational/difficult about a fairly obvious use of the word "normal." Normal is, by definition "conforming to a standard; usual, typical, expected." The percentage of people who are born with a clear and obvious gender and remain that clear and obvious gender throughout their lives is extremely high - likely higher than 99%. I'd say that qualifies as normal.
For folks that do feel that they're in the wrong body or anything of that nature, life is very complicated. I don't feel it, and don't pretend to be able to imagine what that is like. It is absolutely abnormal, but that doesn't necessarily mean the individual is doing something wrong.
Homosexuality is also abnormal, though it isn't wrong. It's simply that the vast majority of people are heterosexual. Similar principle.
Transgender individuals in sports is very difficult. There's a reason girls don't compete against boys in most competitive sports. Someone who finds themselves "in between" probably shouldn't be playing competitively. There's just no good solution. Putting many at a disadvantage for the benefit of one person does not seem logical. It's not a feel-good solution, but I cannot think of reasonable way to include this subset individuals.