Well I think it's all a sliding scale, so there isn't really a binary cut off point, but if you have too many cross gender traits/desires you'll probably find yourself both physically and psychologically very uncomfortable trying to live on the wrong side of the line, particularly if you try to live up to the stereotypical opposite of what you actually are inside.
I'm way to the right of the bell curve, probably 98% percentile, but I also have the genetic factors giving me a delayed puberty, followed by a much extended adolescence of high testosterone, much slower social/brain maturation and so lower self-awareness, and maybe wealthy enough parents to support my rather strange aspirations, and so ample time to pack in the masses of data required.
So, if I'm about 95% female, I'd probably be far better off as a woman in terms of what I subconsciously want to look like, how I want to be treated by others, and what I really want to be doing, but that remaining 5% is the bit that continually tells me I just can't possibly accept the loss of status implied by being a transsexual woman, and anyway I'm actually supposed to be in charge around here, only for some strange reason, I can't quite figure out how to project that kind of authority when I want to, nor can I get it up and get myself off when I really need to.
So I construct for myself an identity/role that allows me to express most of the 95% I do have, like being a professor, or a computer geek, or mad scientist and I'm not going to go to the opposite extreme and build up loads of muscles and join the army because well I don't actually want the muscles, and I don't want to shoot anyone, and that's way too much effort to expend just to avoid being thought of as queer, and isn't really what I want to be doing with my time as I like actually studying things and putting all my effort into making really intricate things that actually work as advertised, and that beat all the competition.
So my ideal lifetime outcome is I dunno, creating a big business that designs, creates and sells small portable trainable humanoid robots I suppose. Only I seem to be a bit behind schedule on that now.
Anyone can just go and get themselves pregnant, but it takes a village or at least a big corporate campus and 10,000+ employees to make something really insanely great. ;-) I always knew I'd do something really special with my life, and I've taken the time to learn most of the skills required, I now just need to find that special magical someone to recognise all my latent talents and give me a leg up... and even then I still just need to find that oh so elusive Higgs Boson, otherwise known as a sperm cell.
But given the recent destigmatisation of transsexualism, and given that I probably could do with having sex about once a year for mental health reasons if nothing else, then I will grudgingly accept that I probably need to transition, and try to actually try to enjoy it, but I still absolutely refuse to accept being bottom of the heap, or something like that. I'm Queen Bitch if you like.
No, it's not an entirely sane life plan, I grant you, but thems the breaks.
(If you could have told me when I was 15 that I could probably just get most of what I really wanted, without most of the stress and effort, and without potentially destroying the planet in the process, and with much more physical health and enjoyment in the process, if I just had a nice sugar daddy when I was 22, I might have taken a very different path in life, but you know, you told me God says it's wrong, and not to lose too much social status by being too abnormal..) ;-)