
Isn't that wrong? It happens, it's just super rare. I did a Google and it sometimes happens because during development one of the twins looses it's y chromosome. 10 cases of the this have been confirmed.
As for behaviour - if they are raised together + look alike they are highly likely to behave in the same way. This is actually a criticism we make within psychology of twin studies where the twins are raised together (we use twins studied to figure out whenever stuff is genetic, twin adoption studied are the best for this.) So yeah, socialised together = likely to behave extremely alike
Although the trans theory would also work.

i didnt know that actually , so its just rare huh. its just more common for male/female twins to not look exactly alike, like any identical twins, cause theyre born like fraternal twins which is why fraternal twins aren't identical either. i understand the behavior thing now cause i have brothers who are identical twins and basically have the same personality. the more you learn i guess lol.
the twin part doesn't even make sense cause male/female twins r born in different bags so they wouldn't look so similar. so in conclusion this would land to one of the twins being trans but in this case