Answer:
Surrogate mother is a woman who has a job to bring the others baby til giving birth safety.
When a couple or gay couple want to have some baby but they have some problem , usually when the couple insist to have their own baby they will using surrogate way.
Using the man's sperm , into the surrogate's body (usually this method called in Vitro Fertilization ). If it works, the woman will get pregnant but the DNA belongs to the real parents.
Sometimes, people said that surrogate mother is just renting her wombs to have some money