What is a surrogate mother? The surrogate mother by definition is a woman who carries and gives birth to a child for the purpose to give it up to another party legally. Sometimes the child is genetically related to her and many times it is not. For the most parts a surrogate mother will be compensated for her role, but there are some women who do it for free, maybe just her legal and medical expenses paid for. There are surrogate agencies that handle much of the process for both parties and many people find going through a surrogate agency comforting and reliable instead of trying to figure it all out on their own. Surrogacy is a highly complicated situation.