Boring! Ask pretty much any parent and they will tell you that they sacrificed decent years of their lives to bring up children. And think of all that stress; the nappies, the crying in the middle of the night. I don't much care for having children, or getting married; its so generic and stifling.
My parents can't wait for me and my sister to fly the nest so they can "get our lives back". They want to travel together but they can't because they had to work and bring up two kids. Therefore parenthood cannot be the best years of your life, its got to be your 20s