Hoi,
The problem that I want to solve is that the number of humans that are neither male nor female is currently 419.862 and growing.
I am not particularly interested in other sex/gender issues. I know from a conversation with DBpedia people that they have a property for "penis length".. Not especially my cup of tea either. I was told that that property exists because of an application in combination with French data ...
The reason for the DBpedia headsup is that their bots run repeatedly. This in contrast to what bots have done so far and, they are interested and willing to report the differences they find. This makes their work superior from a quality point of view.
To be blunt, Wikidata gains the quantitative quality I am looking for when only male and female is added where applicable. Transgender issues with respect are edge cases. I am sure somewhere there is a number of the actual number that might represent them all. John indicated that the quality of that data is poor and his example does not provide the current information.
As I indicated before I am interested in fixing the quantitative quality problem that Wikidata has. To fix this, I am among other things interested in the male and female sex. It allows for studies like the ration of male vs female painters, male vs female authors etc. I am not interested to involve myself in the issues around the transgender sexes. As far as I am concerned, everything that can be easily queried from sources is openly available. If it makes sense to not include particular information, it needs to be raised at Wikidata. It is outside my scope to have more as an opinion.
The one reason why I raise the issue of women on Wikidata is that regularly there are edit-a-thons where people write quality articles about notable females. Wikidata should provide adequate information about what this ratio is for the particular fields that are addressed. It is trivial to query Wikidata to find the number of "profession x" for males and females and calculate a ratio.