I found this question and it feels a lot like troll question. However, I think it needs a solid answer. Speaking as a non-binary person who's seen this s*t over and over.
"sex cells" for me this is just biological essentialism, sperm/egg, and the DNA mention, which will be XX/XY chromosomes, is the same - there will be two only, boom, science doesn't care about your attack helicopter gender. I'd hazard a guess the OP wants someone, stumbling in from some other discipline with more confidence than sense, in order to say something really essential and binary without much else, so it can be hacked up and used as anti-trans evidence.
I think if it's deleted, if the link isn't completely erased then it will be used as an example of "the medical folk don't know".
Even if it is completely erased, then if it's been screen-shot, then erased, the same argument will be made.
If it gets edited at all/too heavily, same argument ...
Ignored. Same argument.
A decade or so ago there was an extreme right-wing christian group who set up something like the "American Association of Psychologists" (notice the difference?) and published lots of anti-LGBT stuff, but all official looking (I might have remembered details slightly wrong, but their basic goal was to look like the Official US. __ then pummel LGBT folk and it worked).
This site already brings tons of that sort of cred just by being SE. Now it's Medical Science, this is possibly a responsibility.
It feels like this sort of question is best dealt with a good answer, even though it's a crap question, just so a unfortunate little artefact isn't handed out to some nasty individuals who use it to hurt people.
Unfortunately I don't know the answer and I hope there is one. I feel like researching it so maybe I will answer. I think there is and it's not too hard if sticking to "sex cells"? ie. yes most people are XX or XY but that doesn't strictly govern secondary sex characteristics, has nothing to do with gender identity, isn't binary etc. etc. all with good back up links.
Would appreciate input, knowledge, of the subject or SE etc.
Of course I could be mistaken, and be calling out a valid question. I read it as "does XX/XY/?? over-ride sperm|egg production or vice-versa when determining human sex"