the.com/surrogacy

means The arrangement in which one woman carries and delivers a baby for another person or couple, who become the legal parents.

from Built on 'surrogate,' from Latin surrogare — 'to put in another's place' (sub- 'in place of' + rogare 'to ask, propose,' the word used for nominating a substitute). Romans used it for standing in as a substitute official; English borrowed that same logic for a substitute mother, a sense that only became common once reproductive technology actually made the swap possible.