Why would you think this would be a turn on for any woman? It's like asking if we consider you being a Republican as a turn on, or a Christian as a turn on, or you supporting school funding and more police as a turn on. It's not. This is like the topic you discuss deep into a relationship or if you know, "something" comes up, and even then turn ons are meant to make you feel good, think happy thoughts. Debating ones right or lack thereof to have an abortion, is none of those things.
It's not a turn on. Nobody wants to think about abortion when they're horny (I assume) but perhaps you're thinking that women who are also pro choice will see potential in you as you seem to have similar views?