Daughters can make their parents healthier, happier, and nicer.
1. Daughters make men more generous.
A recent study found that when a male CEO has a daughter, especially if she's his first child, the salaries of his employees tend to go up. And female employees benefit the most — their wages go up 1.1%, compared to 0.6% for men. Not enough to close the wage gap, but significant nonetheless.
2. They make parents more likely to favor gender equality.
In 2009, researchers found that people with daughters were more likely than others to support policies meant to increase gender equality, and that "people who parent only daughters are more likely to hold feminist views." The effect was especially strong for dads.
3. They're more likely to support their aging parents financially.
A 2012 study [PDF] found that 67% of Baby Boomer women were giving their parents some form of financial support, compared with 62% of Baby Boomer men. Women were also more likely to talk to their parents about finances and long-term care.
4. Having two is apparently the recipe for happiness.
Researchers who studied many different family combinations found that parents of two girls were the happiest — because, the daughters "are unlikely to fight, will play nicely and are generally a pleasure to be around."
5. They can grow up into friends.
In a 2001 study, 80-90 percent of middle-aged daughters reported good relationships with their moms. The study author told Psychology Today that "the relationship between mothers and their adult daughters is one in which the participants handle being upset with one another better than in any other relationship" and "there is great value in the mother-daughter tie because the two parties care for one another and share a strong investment in the family as a whole."
6. They make dads live longer.
Fathers live an average of a little over a year longer for each daughter they have, according to a 2006 study. Sons have no effect. Unfortunately, both daughters and sons tend to reduce mothers' longevity on average. However ...
7. They might improve moms' health.
One small study showed that rather than just getting health advice from their moms, teenage daughters gave their moms advice on better health as well. The study authors wrote that future research should "explore this unique relationship and its potential for daughter-initiated health education."