A child born to legitimately married US citizen parents, anywhere in the world, IS a U.S. citizen. The child may also hold dual citizenship, depending on the country of birth, but the United States recognizes only that the child is an American citizen.

If the child is born to Indian surrogate parents (mother), regardless of who the biological (sperm donating) father is, the child is NOT (repeat NOT) a U.S. citizen. An American man and woman, for example, could go to India (or any country), conceive a child, transplant the embryo into an Indian woman, and the child would NOT be a U.S. citizen. (THis does not include a child born in India to an Indian mother, legally married to a U.S. citizen father, of course. That child may well be a derivative citizen, in that case, dependant on certain circumstances [residency requirements].)