Catelynn revealed at the Teen Mom OG reunion that she and Tyler were "having their final child." And during tonight's season premiere, viewers watched as the 16 and Pregnant sweethearts learned the sex of their bundle of joy.

So how did the couple opt to find out if they were expecting another daughter or their first son? Catelynn took a blood test, and the results were emailed to producer Kerthy so she could buy the appropriate gender reveal popper for the MTV parents. The duo stated they were nervous -- even joking about whether or not Kerthy "grabbed the right color" for the intimate occasion. And when Cate pulled the string, nothing was released from the canister.

After a few tension-filled seconds, Cate got the device to work and an explosion of confetti emerged. All pink, not a trace of blue.

"It's another girl," a subdued Cate declared, as Tyler embraced her. "Oh my God."

"I knew it," Tyler, who has made it absolutely no secret he wanted his own mini-me, offered. "I thought I would have a son. You don't have a son; I don't have a son. It is what it is."

"What are we going to do with ourselves?" Cate pondered, to which Tyler answered, "We are going to raise three girls." Quintessential girl dad.

Watch more of Cate and Tyler's journey every Tuesday on Teen Mom OG at 8/7c as they prepare to welcome their last daughter.