What are you talking about? You agree with "
them" that there: "will never be agreement on what constitutes a biologically born female"? This has been settled for over a hundred years. This thing is simple: if you have xy chromosomes you play on the xy team and if you have xx chromosomes you play on the xx team. No need to discuss anything related to gender when picking teams, nor should it matter how one identifies during the picking process.
Do males have different chromosomes than females?
"Yes, they differ in a pair of chromosomes known as the sex chromosomes. Females have two X chromosomes in their cells, while males have one X and one Y chromosome.
Inheriting too many or not enough copies of sex chromosomes can lead to serious problems. For example, females who have extra copies of the X chromosome are usually taller than average and some have mental disability. Males with more than one X chromosome have Klinefelter syndrome, which is a condition characterized by tall stature and, often, impaired fertility. Another syndrome caused by imbalance in the number of sex chromosomes is Turner syndrome. Women with Turner have one X chromosome only. They are very short, usually do not undergo puberty and some may have kidney or heart problems."
Chromosomes are thread-like structures located inside the nucleus of animal and plant cells.
www.genome.gov