Nothing. It was bullshit from the start.
To the very best of my understanding, three things are necessary to wield the hammer (Notwithstanding the hammer has a strong preference for Thor, who went through many trials to become worthy of it):
- You have to be BRAVE. You have to show courage under extreme circumstances, and do what needs to be done even if your life is in danger.
- You have to be HONORABLE. You have to be good-hearted, fight for justice and be honest and upright.
- You have to be a WARRIOR. You must seek out and do battle against evil, defend the defenseless and, if necessary, slay your enemy.
Many heroes meet one or two of these, but the no-kill rule of Batman and Superman - for instance - prevents them from lifting the hammer without Thor's express permission. Wonder Woman, on the other hand, is an almost perfect wielder.
Notice that "You have to have testicles" is not and has never been a part of it.
I don't know Jane Foster THAT well, but if that woman is worthy, so are very many others.
Now if Sif had lifted it... or Angela (but she would not have)... or even Carol (who, by the standards I mentioned, indeed is worthy)...
But noooooo. Let's get the woman dying from breast cancer.