I think OP is implying that since this person is posting on 4 chan, this person likely already has a birth defect causing some sort of mental deficiency.
Ah but that's where all this gender fluidity/ambiguity gets interesting. OP might be a trans-dude, so "she" (apologies for the hypothetical deadgendering but it's illustrative) would technically then be straight with no risk of butt defects (unless they did that of course) but with some risk of birth defects as he could then have been impregnated by his dad.