Boys mean longer labor what?! (Old wives tales that are true)

Natalie • I'm a stay at home mommy of one beautiful girl and 3 dogs. I'm also an erotic fantasy and paranormal romance author
So I was reading this article on old wives tales proven true ... Turns out that boys tend to have longer labors! But there's more they also have been correlated with back pain too so that explains why my back has been killing me. Also the heartburn is correlated with hairy babies so I think I'm having a puppy lol. You know any old wives tales that have studies with correlations?