I have two wolves of the same sex that I think would make good breeding partners if I use a sex-swap scroll. But there is no way for me to tell if they would before I spend a lot of MS for the scroll, and apply it. If they don't make nice children, then I've wasted a lot of MS that are not easy to come by.
If we could preview the offspring of any two (unrelated) wolves, regardless of sex, this would be an easier decision.