To think they would not have a choice in remaining childfree?

[extarctions]

If the heir to the throne was married but him and his wife did not particular have a desire to become a parent, should their wishes be respected or should the need for an heir force them to become a parent against his will?

What do you think?

It would just pass to the next in line (Sibling, nibling etc) Like if they were infertile. See: Henry VIII.