only thing is they cant have baby but it still count as incest it a dumb law with too much law about it say if you a girl and your father marry my mom to the law we will be brother and sister so what if we was dating before my mom marry your dad do that mean we have to broke up it make no sense there no blood connect at all but the dumb law is dumb i 20 and can make my own chose like you but i guest this only the law in the usa other places i dont know there law too well but internet say much of the world ban incest that why there so most porn about it too show how dumb the law is not allow non blood connect or sis and sis or bro and bro the full point of the law is baby dead but we can save them mostly but human right dont like changing baby dna when they still growing but there more then one way of having a kid that remove the problem using other people seed to allow two people who love each otherlesbian incest!!!!!!!!!, Im thinking dad/daughter or brother/sister son/mom, thats real incest not sister/sister!!!!!!!