You're right, I misunderstood the statistic. It's saying that the fraction of couples with a first-born daughter who have divorced when she's 15 is 9% higher th

You're right, I misunderstood the statistic. It's saying that the fraction of couples with a first-born daughter who have divorced when she's 15 is 9% higher than the fraction of couples with a first-born son who have divorced when he's 15. Bleh, comparing rates is unpleasant business.