I think it would pointless to "ban" these types of abortions. After all, if I wanted an abortion and knew certain reasons wouldn't grant me one, I could very easily just lie. So what then? Just ban all abortions? (Pro-lifers, no need to quote and say, "YES!"... my question isn't posed to you... more to those who claim to be pro-choice, yet want stipulations).
I am still in complete support of a woman's right to make this choice. Some women will do things that make me uncomfortable with that stance, but so many more women will choose to abort for reasons I (and many others I suspect) feel are far more "valid," than whether or not a gender scan says you're having a boy or a girl (and seriously, the results of those aren't infallible anyway).
I think putting stipulations on reasons for wanting an abortion is stepping into dangerous territory, and is almost the same as any pro-life argument. It's still, "I, a stranger, know more about what's best for you than you do."
And trust me, I've heard some horrible crap about abortions... but I still think the "greater good," is to grant all women the right to make the choice to abort... regardless of their reasons. In Australia at least, there's unlikely to be a large percentage of women making this call because she'd rather have blue linens than pink.