What if you learned that a completely frivolous celebration you had planned could result in bodily injury, a massive explosion, a devastating fire or even death? Now add to it the fact that the guest of honor would be pregnant. Would you still host it? Based on the growing popularity of gender-reveal parties over the last decade, the answer for many is a resounding yes. 

It all started innocently en-ough. In 2008, pregnant blogger Jenna Myers Karvunidis gathered her family to cut a cake: The pink-hued contents announced to all (Myers Karvunidis included) that her first baby was a girl. The Bump picked up the story, and a hot new trend was born—as well as her daughter Bianca.

Alongside the rise of social media (and concurrently, an almost Pavlovian obsession with going viral), excited...