I need your opinion about this hypotethical (but entirely possible) situation.
1. Let's say that Prince William of Wales marries a Roman Catholic tomorrow and thus forfeits his right to succeed to the British throne.
2. His brother, Prince Henry of Wales, would become third in line of succession and eventually heir apparent upon death of his grandmother or father.
3. Now, when Henry is the heir, his elder brother who has forfeited his succession rights becomes a father. His child is not brought up as Roman Catholic, so (s)he is eligible to succeed to the throne.
4. Now a problem arises: according to the rules of primogeniture, William's child would take precedence over Henry in the line of succession. Would this child indeed replace Henry as heir to the throne?
Perhaps Henry wouldn't become heir apparent if his brother forfeits his succession rights, but only heir presumptive, since losing a place in the line of succession doesn't prevent a person from producing children who are eligible to succeed. In other words, Henry would be an heir until William fathers a legitimate child. Right?
But then again, what if William's child is born after Henry's accession? Would that child's birth end Henry's reign and would the child automatically become monarch (like Queen Victoria's reign would have ended if her aunt gave birth to a live child)?