Michigan Couple Welcomes 13th Son

It's a boy ... again!

Kateri and Jay Schwandt, a Rockford, Michigan, couple who have 12 sons, welcomed their thirteenth boy to the world on Wednesday.

Kateri, 40, gave birth a few days after her May 9 due date, according to ABC News. The baby weighed about 9 pounds and was 22 inches long.

Kateri Schwandt gave birth to son No. 13 on Wednesday, May 13, 2015.

In an appearance on "Good Morning America" earlier this month, Kateri said she assumed her 13th child would be a boy.

“I just assumed we’d have another boy because we know what we’re doing," she said at the time.

It turns out she was right.

The couples' other children range in age from 1 1/2 to 22 years old. Jay and Kateri haven't decided on a name for lucky No. 13 yet.

Jay and Kateri Schwandt with son No. 12, Tucker.

The couple observes a tradition of waiting until birth to find out the sex of their babies. Although Jay told ABC that "[having] one more boy is pretty cool," he had hoped for a girl.

“I’ve experienced all the boy stuff,” Jay told The Grand Rapids Press last year. “As long as we are having all these children, it would be really neat to experience the other side.”

Kateri saw things differently.

“Why change things up?” she told WXMI last year, after she announced her pregnancy. “At this point, at this stage in the game, a little girl, we’d have to re-learn everything.”

The odds of a couple having 13 sons in a row are about 1 in 8,000, according to CNN -- roughly the same chances as those of having natural triplets.

Moreover, just having 13 kids is quite a feat. The average family size in the United States is 3.14 people, according to 2010 census data.

Will the Schwandts try for 14?

"You never say never," Jay told ABC.

The Schwandt family in August 2013.