I agree surrogacy allows infertile couples to have children. It also allows gay couples to have children. I believe that if a couple is responsible they should be given the chance to begin a family. Unfortunately some couples for whatever reason are unable to have kids -- I don't believe this is their fault.
I agree that surrogacy is would be all right in certain emergency instances. For instance, if a woman has had many miscarriages although she has the ability to become pregnant by her partner, then surrogacy might very well save her life and would definitely allow the fetus to develop into a baby. This would be the correct use of surrogacy. It could be used if there is a danger of a woman who has conceived dying in childbirth because of a heart condition or other organ problems. A surrogate mother could then be hired to bring a fetus to term and give birth without endangering the actual mother of the new child. However, frivolous use of surrogacy, such as preserving ones figure from stretch marks or simply not wanting to get pregnant and have a child should be prohibited.
Not every person who wants children wants them or their partner to go through the trials of pregnancy. Surrogates who agree to be pregnant with the child should be allowed. This would allow the surrogate to potentially be paid and the parents to enjoy having a child, everyone in this scenario wins.
Exploits women. If we are unable to have a baby naturally, isn't that nature's way of telling us that it is not meant to be? Sure we have the technology but is all the pain and money worth it. There are many children that are parentless that need help why not help them?