The Church's teaching on the immorality of in-vitro fertilization seems cruel and unfair. Don't married couples have a right to have a child?

While the Church’s judgment concerning in-vitro fertilization treatments may appear cruel and unfair, it is not. Children are a gift, not an entitlement. Beyond the horrendous acts that accompany the IVF process, one should recognize that the human person, from the moment of conception, has a dignity that is to be respected. It is not to be used, manipulated, and destroyed so that a woman can have her "right to have a baby."

The Church teaches that

[M]arriage does not confer upon the spouses the right to have a child, but only the right to perform those natural acts which are per se ordered to procreation. A true and proper right to a child would be contrary to the child’s dignity and nature. The child is not an object to which one has a right, nor can he be considered as an object of ownership: rather, a child is a gift, "the supreme gift" (58) and the most gratuitous gift of marriage, and is a living testimony of the mutual giving of his parents. For this reason, the child has the right, as already mentioned, to be the fruit of the specific act of the conjugal love of his parents; and he also has the right to be respected as a person from the moment of his conception. (Instruction on Respect for Human Life 8)