As a 100% DL with no AB tendencies, I can only speculate. I read somewhere that sissies want to experience what they never did, life as a soft, sweet, gentle baby girl.
Does that make them transvestite babies? I don't know. There are so many different slants to this thing it is hard to get a straight edge on it. There's more than just daddies, sissies and DLs. If you mix in sexual orientation and gender identification, it gets to be a very large mix of values.
I do suspect that those afflicted/endowed with the sissy syndrome are much more likely to be vocal, aggressive and out about their choices and preferences, persuing them to the exclusion of some other social functions.
Just an opinion based solely on personal experience.