Just as contraception is the deliberate exclusion from the sexual act of its procreative end, so in-vitro fertilization is the deliberate exclusion of the unitive dimension of spousal love from the conception of a human being. That is, the sexual act is intended by God both to nurture the love of a husband and wife, as well as open them to His creative act in the generation of human life. When these dual ends of sexual relations are fractured - when the sexual act blocks its procreative meaning through contraception, or when procreation is severed from the spousal union of love, as in in-vitro fertilization and artificial insemination - it constitutes a grave violation of the moral law. The act is rendered even more serious when, as is often the case, "surplus" embryos must be aborted to make way for the embryo that is chosen for survival. The gravity of the act is exacerbated still further when persons other than spouses donate the sperm or the ovum (surrogate uterus) since such actions violate a child's right to a father and mother, known to him or her and bound to each other in marriage.
