GYN questions

Alexandra
Okay, so I have never been to a gynecologist. Well, I have been one time but that was before I was sexually active (though they refused to believe I hadn't ever had sex, and it was a horrible HORRIBLE experience.) I am terrified to go to one. And when I say terrified, I don't mean nervous, I mean I have literally come to terms with the idea that I would rather die from cervical/uterine/ovarian cancer than go to a gynecologist. I'm absolutely serious about this.
But I wanted to know, what else do gynecologists screen for? (Other than stds, I'm monogamous and I know I shouldn't trust someone when they say they don't have stds but I do trust my boyfriend when he says it.) like honestly, other than cancer, what's the point? I never plan on having kids (I don't want to pass down my terrible mental illness genes, if I do want kids, I'll adopt.), so I don't care if I become sterile. 
What is the point of going to a gynecologist?