I don't actually see the problem. Someone is going to have to at some point let my child develop in their womb. That's a pretty big reality. The majority of my friends would not be qualified for this and the ones who would be don't ever want to have children. So I would have to hire a complete stranger to do this for me. This idea is terrifying to me. I don't know what they're going to do. What if they smoke really quick one day? What if they aren't eating right? I know that normal agencies keep track of things like that but I don't believe in "agencies" keeping track of things.
Assuming you ever told the kid (because there's really no point) what's more weird "Mommy had to pay a stranger who we will never talk to, to have you for her because her insides are broken" or "Mommy had her good sweet friend who is always around have you for her because her insides are broken"?
I don't see the difference between sub and let's say friend or sister. Though I'm sure to others this may sound like their sexual fantasy for me it's not.
(sorry if i sound frustrated... Brain freeze while typing).