BOSTON -- The Fourth of July may be the official birthday of the United States, but the date also belongs three Massachusetts boys, including a newborn set of twins, and their dad.

The Mahoney twins weren't due until July 14, but when their mother, Edina Mahoney, 30, of North Reading, started having contractions during July Fourth celebrations, she underwent an emergency C-section at Brigham and Women's Hospital, WCVB-TV in Boston reported.

Now, twins Michael Jr. and Joseph join both their father, Michael, 51, and their big brother, Paul, 17, in sharing a July 4 birthday.

"You don't have to worry about who's born when, that's for sure," said Michael Mahoney, a Lynn attorney.

All the Mahoney boys, including Paul, were born earlier than expected, but Edina said the matching birthdays were a complete coincidence.

"If you’re pregnant, or you know something about hospital policies, you know you can't schedule a C-section on holidays," she said.

Paul said he didn't expect to add two more to the family birthday, calling it "pretty crazy."

"I'm sharing my birthday with all these guys, so it takes a little bit off of me, but I don’t really care," he said. "It's cool."

The patriotic gene did not extend to the women in the family. Another sibling, 3-year-old Lily, was born in December.