as a way to avoid crossing the line from pornography to obscenity.  They're being way too cautious because almost anything goes these days.  The only obscene material the law goes after these days seems to be child porn.  

 
I've seen clips listed as "real father-daughter" but they haven't been busted for obscenity, probably because it's obvious they are actors.  
Sometimes they don't use "step" and instead say "Mother fucks not-her-son."  Not-her-son...lol.

And whether we like it or not, there sure seems to be a large market for implied (or not) family sex videos and other material. If the producers were not getting a lot of views/reads (money) it would largely disappear.  Some apparently valid reports/articles seem to suggest that incest is more common in families than is normally thought.  A very small percentage I would think, but in a population of 300 million even 0.05, for example, is a lot of people. I do have some personal experience with this and do not take it lightly.

I'm totally over the whole boinking your step- whatever, too. I also find it creepy, and I think that had a hand in driving Rayveness (one of my all-time faves) out of the biz. I saw something from her (tweet, or instagram post -- can't remember exactly) where she essentially said, "I'm tired of being someone's step-mom."  

I don't know why they can't stick with the old standbys -- fucking your neighbor, your teacher (or student), your co-worker, your friend's spouse, your friend's mom, etc. Or hell -- even your own spouse. Angela White as a couple really hot VR scenes in which she's fucking her "husband."  

Years ago, I saw a scene in which Scott Irish and Candie Evens played a brother-sister who fucked. She went into his bedroom to see if he wanted to go to the beach. He was all upset because he couldn't get laid, so she said she'd take care of hit. It was a hot scene (Candie was gorgeous), but I couldn't get past the fact that they were pretending to be actual siblings -- even though it obviously wasn't real. It just sorta grossed me out.  

But unfortunately, there doesn't seem to be any end to that theme any time soon. I'm a big fan of Natasha Nice and it seems as if about every scene I see of her these days is her having sex with her "step-brother." Bleh -- don't care for it.

i dont care for the fake step brother and sister thing either.
it’s seems really wrong but the real sisters together is hot.  

two hot latina sisters used provide together in san diego and interact w each other. queen b and sis. always wanted to but at 2k it was out of my price range.  

are the ortega sisters from Venezuela actually sisters?  

I always found it wierd when real sisters appear in porn in thr same scene. Most recently Sami and Joey White were getting piped in a few scenes with the dick literally going from hole to hole in rapid succession while they were stacked on top of each other. I mean thats literally exchanging fluids not to mention the creampie that was pumped into both. Mia And Ava Rose had a similar on screen relationship.