How can you sell a piece of yourself? After all, trafficking in people is illegal. So why is it allowed to sell unborn children yet? In addition, a woman bearing a child is inflicted enormous harm to her body which is not worth any money. In addition, such children will be weak and more likely to get sick. This is a very dirty business.
There is no evidence to prove that surrogacy is harmful either for the mother or the baby. Most of the babies are healthy and they face no long-term health complications. And in countries where the average salary is like $1,000 per year, a one time payment of $20,000 or $25,000 can go a long way in eradicating poverty.