Kourtney Kardashian posed nude for DuJour magazine, because she thinks she's really pretty when she's pregnant. I get the whole beauty of life/birth thing, but just looking at her makes my uterus hurt. She wants to make sure she has a picture of her children when she's pregnant with them so she can show it to them and say “This was you inside.” That sounds like something she would say to Scott while filming a sex tape, not to future mortified teenage kid.
So now Kylie is the only Kardashian-Jenner woman not to have taken nude pics. She's also still a minor so that'd be child porn but Kris Jenner has got to be counting the days for her debut.