This corroborates other studies, this is likely how transgender folk are born. Something as normal as hormonal changes in the parent after the brain is developed with a particular sex blueprint can mean the body, sexual organs, are developed a la the opposite sex. Of course, the human experience and every aspect of a life is a dot on a scattergraph - some folk display more femme traits and some more masc traits, independent of sex.
Yes, reproduction is important as a species but it's not that important when you have so few natural predators, and one reason humans are special is our ability to be complex.