The fact that the couple wants a surrogate mother implies, probably, they have considered the option of adopting but they do not want to proceed. If they are aware that a child can be born this way, they cannot be ignorant about adoption.
Why they do not proceed for adoption is a personal choice, IMHO. It can be an emotional issue or a perception about genes. Every couple wants THEIR OWN CHILD. If that was NOT AN EMOTIONAL ISSUE, having known that there are thousands n thousands of children that can be adopted in our own country, we would not have been so populated nation and if not all, many many couples would have simply "adopted a readymade" child.
