Surrogacy is simply using the womb. It is not interbreeding, so it does not necessarily imply they are the same species. There are many definitions of species.

Surrogacy is simply using the womb. It is not interbreeding, so it does not necessarily imply they are the same species. There are many definitions of species. If they are able to interbreed and create viable (i.e. non-sterile) offspring, they might be considered to be the same species. However, there are cases where offspring are viable, but less fit for a variety of reasons. In this case, many biologists would still consider them separate.