if you like to mislead yourself with your own experience and theories, do not mislead the world.
let aside nature and religion. simply look around and find out how many families are there with "planned" single parent.
not convinced? go to any mall over the weekend. count how man kids are accompanied by both parents and how many are with single parent (thought this does not mean the other parent does not exist).
even gays and lesbians, tend to marry (same sex) and adopt a kid to establish a complete family (according to them).