> Biologically, a woman is a human with two X chromosomes. This would be the best scientific answer I would give if someone asked me that question.

But science knows better, as will you, after reading https://en.wikipedia.org/wiki/Klinefelter_syndrome, which says:

“Klinefelter syndrome (KS), also known as 47,XXY, is a syndrome where a male has an additional copy of the X chromosome. The primary features are infertility and small, poorly functioning testicles. Often, symptoms are subtle and subjects do not realize they are affected.”