Dan and Patty MacInnis were hoping for a son to carry on the family's Scottish surname, but had three daughters. Luckily, one of those daughters found an amenable fiancé in Gary Fletcher.
Seems that about six weeks before their wedding, Heather asked Gary to consider changing his name. First he was very quiet, she said, but "he let me know he'd think about it."
After much thought and realizing his brothers could carry on his surname, Gary agreed to legally change his last name to MacInnis. [Link]