It's just common sense, people are more open to anal now than they were then. Just look at porn through the ages, it's a huge tell-tale of what's going to be the next "thing", it also shows hwo things have changed. Back in teh 60's oral was the big taboo in porn. I remember watching a 70's porn that had a woman going Vagina-to-mouth GASP! Then I saw a late 70's porn that dealt with first time bisexuality in women where one eats pussy for the first time. I remember the early 80's porn that first introduced anal(although it did happen in some earlier films, it was almost unheard of). By the late 90's anal was included in about 80% of all porn and the new "big thing" was ATM. Now 99% of all porn includes anal, 80% of THEM have ass-to-mouth. There is no more porns that discuss the tabboos of girl-on-girl and 99% of all porn actresses will to it with girls. the vagina-to-mouth topic is completely extinct and long lost to time. With the steady increase of DP vids and massive gang bang vids, plus vids that include women tossing salad and fingering mens asses during blow jobs, I suspect a genre of bi-porn will emerge that will be considered "straight" and "Manly", this will begin to break the same wall that once stood between straight and gay sex for women, where as now girl-on-girl doesn't even mean gay anymore, it's just what all women do and no one bashes an eyelash for it anymore.