Re: "actress"...yet another perfectly useful word forever tarred with the brush of political incorrectness. Female actpersons might refer to themselves as ActorS, but there are still many people who refer to them (quite respectfully) as ActresseS. It's what they are, isn't it? -- AnonymousCoward (ducking)
Linguistically speaking, what is common usage IS correct. These females who act are, as a group, whatever the plurality of AME speakers call them, be it ActorS or ActresseS. THAT IS WHAT THEY ARE!!!(Answer to A.C.) Since there is a dispute here, started by me, I will cede to the older nomenclature and possibly the majority opinion. I have created ActresseS. Wait til next year though...:-).
In both cases, there is a good reason for the distinction. If men and women played in the same tennis league, it would be extremely unfair. That's a biological fact, as far as I know. Maybe in the future, it will not be true, but for today, it is true.
In acting, it is generally, but of course not universally, the case that parts played by women and parts played by men are inherently different. It might be possible to remake, say, TheGodfather?, with MichellePfeiffer? playing the role previously played by MarlonBrando?, but...
If we were making a page listing famous philosophers, or famous scientists, I do not think that a separate listing would be a good thing at all. Unless, of course, someone wanted to make a page highlighting famous female scientists of the past, when they were more rare, or something like that.
One of the beautiful things about a wiki is, of course, that someone can create a page of 'ActingProfessionals?' that lists all of them, male or female, on the same page, or in alphabetical order, like 'ActingProfessionals?/A', etc.