In July, a California mother gave birth to her fourth child — remarkably, all four of her children share the same birthday: July 7. According to Professor Randall Swift, chair of the mathematics department, the odds of this happening are so rare that you're more likely to win the Powerball lottery 100 times than have four children born on the same date. He estimates the probability of four unrelated people sharing the same birthday at just 0.000000000056349 percent.

This article was originally published by Los Angeles Times on July 26, 2025.