Is a surrogate a mother?

Alexa

http://www.slate.com/articles/double_x/doublex/2016/02/custody_case_over_triplets_in_california_raises_questions_about_surrogacy.html

I hesitated in posting this article, because I don't want it to be an abortion debate. But it sparked an interesting thought.

To summarize the article, a man paid for a surrogate to carry a pregnancy for him. He paid for the pregnancy plus offered additional funds if she carried multiples. They implanted an embryo with his sperms and another donors egg. The embryos are not biologically related to the surrogate. They implanted three embryos and all three took. The man then wanted the surrogate to terminate one of the embryos, leaving two. The surrogate refused and now they are in a legal battle to decide who has the true rights over the pregnancy.

I truthfully don't know how to feel! On one hand, he paid for a pregnancy and offered additional payment for multiples, so he clearly knew multiples were a possibility. On the other hand, does a surrogate have a say over what happens? She's in a paid contract. Does the man deserve to make demands over services he's paying for?