Gestational surrogacy is actually a type of surrogacy wherever the surrogate (or carrier on the pregnancy) isn’t genetically relevant to the fetus simply because they failed to give the egg useful for fertilization. The intended mum or dad’s egg or a donor egg is used in this kind of pregnancy. https://www.whofish.org/Default.aspx?tabid=45&modid=379&action=detail&itemid=286084&rCode=33