Michael Phelps and wife Nicole expecting their second child

Michael Phelps is racking up offspring almost as quickly as he did gold medals.

In a series of Instagram posts featuring their 15-month-old son, Boomer, holding positive pregnancy tests, Phelps, 32, and wife Nicole announced that their second child is on the way.

The couple tied the knot in June 2016, but didn’t announce their wedded bliss until after the Rio Olympics.

The 23-time gold medalist and Nicole don’t yet know the sex of their child, but previously said that they’d like to expand their brood.

“Nicole has recently brought up that she would like a girl,” Phelps told People in June. “We definitely want more kids, it just depends on when. I’m sure I’m getting pressure.”

He added that though Johnson’s first pregnancy was unplanned, the next will be deliberate, saying, “[We’re] trying to get moving on some things!”