Halachic Source for Women-Only Mikvaoth?
There are dedicated mikves (pool) for men and women.
A friend said me that the reason of this separation is that a woman can't go after a man in the mikve because there is a possibility that the man left some zera which can go in the woman and she could be pregnant.
It was unable to give me a source but an other person gave me the same reason (but also without source)
This reason sounds a it strange for me: the probability for that event happens is very low to decide this prohibition.
Does someone have a source of this takana or an other reason to the fact that a woman does not go in the pool after a man ?