While it is true that biological sex is typically determined by the presence of male or female gametes, which are produced by the gonads (testes or ovaries), it is important to recognize that there are variations in the development of these gonads that can result in intersex conditions. These variations can include differences in genitalia, hormone levels, and chromosomal makeup that do not fit neatly into the male or female categories. While these variations are relatively rare, they do represent a diversity of biological sex that goes beyond the traditional binary categories of male and female.
However, I understand your point that the traditional binary categories of male and female are based on the presence of male or female gametes, and that this is the primary determinant of biological sex. It is important to recognize and respect the diversity of biological sex, while also acknowledging the limitations of our current understanding of this complex and multifaceted aspect of human identity.