this is all real interesting.... I believe that if your good at oral then no matter if its a male or female you will be good... my past girlfrinds have always loved when i suck on their pussies. So, although i have never done it, i believe that i could suck off a dude fairly well, its all about how you use your tongue, lips, suck and whatever.... My last girlfriend, and now somewhat of a fun buddy can suck cock like no other, she simply loves to do it. so i believe she could prob suck a pussy just as well. where as my girlfriend before her could not suck dick at all...it was almost more toture than fun. she would also prob suck at sucking pussy, although she knows what feels great and what does not.
I hope this insight / thought helps... i have been drinking some and it makes sense to me..lol.