Kourtney Kardashian gender reveal

Kourtney Kardashian is about to be outnumbered.

The pregnant E! star, who already has a son and a daughter with partner Scott Disick, announced on Kourtney and Khloe Take the Hamptons that she's going to have a second baby boy.

"I'm so happy to be having a boy," she said. "It's going to be perfect for our family."

Kourtney's nearly 5-year-old son Mason participated in the big reveal (as did ubiquitous sister Kim). Kim filmed the whole thing while Mason showed the family a colorful item that corresponded to the gender news: "Mason ran in here with the blue stick. There was a red star or a blue star," Kourtney said.

(The gender reveal trend, of course, has popped up in the form of reveals by way of cakes filled with icing, balloons hidden in a box, or other pink or blue surprises.)

Evidently little Mason had wanted another sister along with 2-year-old Penelope, but auntie Khloe helped him find enthusiasm for a little brother. "Girls don't like aliens and Lego guys," she said. "When you have a brother you can say 'Look at all my Lego guys, brother.' You get to be rough and you can boss him around because you're the older one." (Is that how it works?!)

Congrats to Kourtney on baby number three to-be!

Photo courtesy of Instagram/KourtneyKardash

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Alesandra Dubin is a Los Angeles-based writer and the founder of home and travel blog Homebody in Motion. Follow her on Facebook, Google+ and Twitter.