Gender neutral language creates different groups of people and is actually more precise. Woman is not a synonym with "person who menstruates." In fact there are huge numbers of women who don't menstruate...all women who have gone through menopause, just for starters. Person who menstruates is no more awkward that "woman of childbearing age" and also includes people who menstruate who are not women.

It doesn't erase the term woman. I am a woman. Pretty soon I will cease to be a person who menstruates. I will not stop being a woman.

We do need a word for non-binary sibling of parent, though. I hadn't even realized that one was missing.

(And nibling is a useful term for everyone, it's shorter than "nieces and nephews," after all).