The surrogate mothers are primarily the women who had already their own kids.
They said that they do that just for pleasure not for money (they even have a good job).
They want to help other people out with infertility problems including gay couples. They even enjoy pregnancy.
I hardly understand their mind. Usually, a mother is to have a strong bond with her fetus during pregnancy. But the surrogated moms mentioned above don't on the pretense that they are pleased to help others out.
Whatever, I think it must take time me to figure out their unusual thoughts.