I unfortunately can't speak to the societal aspects of your question, but I would like to point out that gynecology at some level has existed since at least classical times, as evidenced by this speculum and other similar instruments found at Pompeii and elsewhere. To ask who the first modern gynecologists were is to assume that at some point in the modern era the specialty was rediscovered, as opposed to constant practice in some form since at least the ancient Greeks, if not earlier.

Men certainly dominated the classical medical practitioner milieu, but it seems clear that women were involved in medicine among both the Greeks and Romans. Period artwork usually depicts women functioning as midwives for childbirth and it is not a great leap to assume that women would handle not just childbirth but all womanly medical issues. I'm not aware of much art depicting routine exams that would confirm that supposition though admittedly it is not my specialty. This lamp sherd seems to depict something along those lines but it is difficult to determine whether it is a male or female performing the procedure on what is clearly a very ill woman.