If it is legitimate to vote for a candidate based on their position on abortion, or 'being tough on crime' (aka...

If it is legitimate to vote for a candidate based on their position on abortion, or 'being tough on crime' (aka locking up black people), or sharing bathrooms, why is it not legitimate to vote for a candidate based on gender? This came up when Clinton was running against Obama, too. You shouldn't vote for a woman just because she's a woman. Oh, ok. I guess there are no gender issues of importance, then, that might have political or legal avenues of address.

I do not mean that you should turn your brain off and just vote for people on single issues; it's preferable not to. However, if you are going to make decisions on single issues, why isn't gender and its treatment in society a legitimate issue? Women were basically not legally people under the laws when the US Constitution was written. They couldn't vote until 1920 (technically I think NJ gave them the right to vote originally but it was overturned by laws passed in the early 1800's). Scalia didn't think the 14th amendment protected women's rights (details, details).

So for the third time, if you're going to vote on single issues, why isn't gender just as legitimate as any other?