They both had the same due date, so they knew their babies would arrive around the same time.
However they, along with their family, still can't believe they gave birth just 22 hours apart.
"It's still just so surreal - the whole thing is surreal. I can't believe I am a mom. I can't believe my little sister is a mom," said Brigid Bink.
Last winter, she and her husband Lee found out they were going to have a baby.
Her sister Emily Whitaker and her husband Colin got the same happy news the very next day.
The sisters spent the last nine months, bellies getting bigger, going through pregnancy together.
"I don't think I could have done this pregnancy without her," said Whitaker.
On Wednesday, at 7:34 a.m., Brigid gave birth to Jack. He was born 7 pounds, 6 ounces, 20.5 inches and became the family's first grandchild.
A very pregnant Whitaker came to Abington Memorial Hospital to see her sister and new nephew.
"I brought my hospital bag thinking, 'Okay this will be it,'" said Whitaker.
However she went home, and then went into labor.
On Thursday morning, at 5:39 a.m., Owen came into the world at 8 pounds 9 ounces, 21 inches and just 22 hours after his cousin was born.
"When she called me this morning and told me she had a boy too, I just started bawling," said Bink.
The couples have big plans for these little guys - bright futures for two cousins born in the same spot just hours apart.
"Going down the shore - being in each other's weddings," said Bink.
"I see them playing sports together - going to school together," said Whitaker.
"We got the starting shortstop and the second baseman for the Phillies in 2034 now," said Lee Bink.
"It's been nothing but good news and great times," said Colin Whitaker.