Let's look at Miriam Webster's definition of the word "species":
d (1): a category of biological classification ranking immediately below the genus or subgenus, comprising related organisms or populations potentially capable of interbreeding, and being designated by a binomial that consists of the name of a genus followed by a Latin or latinized uncapitalized noun or adjective agreeing grammatically with the genus name
What this means in shorthand is that a species is defined as a type of creature that can mate with another of its kind and have fertile offspring. Just to illustrate, a mule is not a species, since it is the offspring of a horse and a donkey. Thus, rather than a species, a mule is a hybrid. Don't start telling me about some dude that's pregnant in Hawaii. This is not a biological man. This is a transsexual. He/she/it was on Oprah, and you know what else is on Oprah? I won't go there. This individual has no pronoun that applies since this individual is a mutilated woman, and not a biological man.
And then, you have hermaphrodites. The banana slug, for example, is a hermaphrodite. (I know some of my links are in poor taste, I just can't help myself.) More to the point, each fully-formed banana slug produces eggs and sperm, and has a penis. When two banana slugs mate, they violently stab each other with their penises to the beat of Marvin Gaye (or Isaac Hayes if they are scientologists). The point is that they have no gender definition between them, as fully-formed humans do.
I have never heard of two biological males that can have any sort of offspring together, much less a fertile offspring. This means that males do not by definition specicate from females. The proper terminology is "male sex" or "male gender." Maybe some people get too hot whenever they use the term "sex" and aren't smart enough to know a big word like "gender." If that were true though, where did they learn the word "species"? Oh, wait! They didn't! That's why I'm writing this - for the education of it!
I think a lot of this stems from radical feminists. You know the types. I'm talking about the ones who call themselves "womyn". Just so you know, "womyn" is not a word, it's a joke. The book of Genesis defines the word "woman" as "out of man." Now that being said, a woman has a right to be a radical feminist. I have the right to think that they are stupid. I don't think women in general are stupid in the least, but radical feminists? You betcha. I will offer the latter a couple of alternative ideas to make the word "woman" just a little more palatable.
If we consider the "out of man" definition, you can take this one of two ways. If you believe in a theological, "then the LORD said..." creation, woman (Eve) was literally created from tissue taken out of man (Adam). This is not a popular view among atheists or some other types of people. You may chose to believe that "man" refers to "mankind" in which case, "out of man" is quite flattering. In this definition, women are set apart from mankind as something special. I choose to look at the word "woman" from both viewpoints, as I do believe in a theological creation, and yet I think that women are pretty freaking amazing creatures! I love them, think that all men should love them, and it's really sad the number of men that do not give them the respect that they deserve.
Let's not get into the whole chicken-and-egg discussion on this deal. As we all know, since men - who grow up from boys - are born of women, the argument could easily go that way. But as we have ultimately learned, it does in fact take two of a species to tango, and that's exactly what makes man (as in mankind) a species. I have a dream that all men (as in mankind) will one day speak and write like adults with a full command of their first language. In my dream, men (as in the species) will not have to make up childish names for themselves and each other or use words incorrectly, for they will have risen from the ignorance that currently enslaves them.
...just my $.02...