The actor is stepfather to his wife`s three kids with ex-husband Bruce Willis - daughters Rumer, 21, Scout, 18, and Tallulah, 16 - and admits he is glad the girls are growing more independent as it gives the couple more time alone together. When asked about the possibility of them having a child together, Ashton said: "There is something attractive about our third girl - she`s 16 now - gaining some independence. I get to walk the dogs in the morning because she can drive herself to school now. There is a level of independence that we`ve never had since our relationship started, and an ability to spend time together doing things that we might want to take advantage of. Because in our relationship we`ve always had kids. "We get to do a lot of things now... There is something very attractive about what we can do in the world and for the world, given that responsibility in a different place." However, the 32-year-old star laughed off the possibility that his 47-year-old spouse is too old to get pregnant again.` He added on US TV show ‘Nightline`: "I think my wife is a genetic freak. I`ve no worries there."