I am suggesting that there is no scientific evidence for a genetic cause. That is a simple fact. But the Left posits a genetic cause without evidence (that's the anti-science part) to gain certain political advantages. For example, government benefits can then be given as a matter of right, instead of as a result of successfully arguing costs & benefits in a Congressional floor debate. The Left is suggesting a scientific theory without evidence to shut down floor debate.
This is especially true on the transgender issue, and even on the abortion issue...both of which are well settled with regard to science, but not politically well settled. At least with homosexuality, you can say, "We haven't found the genes yet (or the other biological causes yet), so they may exist." You can't say that regarding the definitions of biological sex and the beginning of the biological life cycle. Those concepts are well settled, and you have to either deny the science (so your political argument is easier), or you have to acknowledge the science (and face up to the harder political argument). Using politics to change science is very Orwellian, to be sure, but at a minimum, it is also very anti-science.