>>14147719Depends how loose your definitions are. If you use lose enough definitions you get as many as you'd like.
By the classical definition: 2
By the standard of those who believe "gender" is entirely self defined: no limit.
It's more a question of semantics than science.
It's worth noting that pretty much all mother who have had male children have a miniscule number of male cells in their bodies, as they absorbed some stem cells from the developing foetus. So a naïve genetic definition isn't perfect.
You could theoretically create a male/female chimera person with 50% male cells and 50% female cells who would be difficult to classify by any standard unless one of the cell cultures ended up structurally dominant.
There are also plenty of organisms who have fewer or sometimes more than 2 sexes, and some that can switch back and forth depending on conditions. No mammals that I know of though.
