The other end of the spectrum is debtors' prisons, which are such a terrible idea for multiple reasons that we've mostly gotten rid of them (except for situations like child support debt where self righteous indignation overrides good policy).
From a ruthlessly clinical evolutionary game-theory perspective... It's also that someone who spreads their genes by creating a child is obtaining a kind of "asset" for themselves, one which society can't transfer and won't morally destroy in retribution.
If A and B both invest in, say, a house, and B disappears leaving debts behind, at least A can sell the house and B isn't getting any ongoing utility from it.
There is value in spreading genes, but also in spreading memes. The biological patents give the former, the adoptive parents give the latter. As this is an agreement that all parties consent to and it has consideration for all involved and say its a valid system.
I'm not convinced. I make investments in the hope that I will end up getting back from it more than I started with; ideally by enough of a margin to cover the time I had to wait.
My genetic future isn't any kind of investment. I'm never seeing any return on that.
