That's just false, and shows a blindness on your part to the overwhelming gender cues and conditioning that go on in society. Next you'll be saying girls "just naturally love pink, it's biology!" Further, saying "most choose not to" is a total cop-out. Why do they choose not to? Your suggestion that it's overwhelmingly biological is, again, just false and ridiculous in the extreme. CS environments are frequently unfriendly to women, and comments like yours are specific examples of why.