what defines sex ? Eggs or sperm do. All of those combinations are either eggs or sperm phenotypes ( or infertile ) ; there’s no third type . Sex is of course only two complementary opposite types in sexually reproducing species. One of each required for fertile sex. No third type required or able to be part of reproduction. Anthropology includes human evolution, biology. I _teach_ biology .

what defines sex ? Eggs or sperm do. All of those combinations are either eggs or sperm phenotypes ( or infertile ) ; there’s no third type . Sex is of course only two complementary opposite types in sexually reproducing species. One of each required for fertile sex. No third type required or able to be part of reproduction. Anthropology includes human evolution, biology. I _teach_ biology .