He built the tree house. Wiped away tears on a tough day. Cheered on the sidelines. There are lots of obvious reasons to appreciate your old man, as many in the United States, Canada, and the United Kingdom will do this Sunday, Father's Day. (Related: "Father's Day at 100: How It Began, Why Dads Get Fewer Gifts.")
But new science on fatherhood is uncovering others that you may not have known—and which should earn Dad a little extra love.
Boosting Daughters' Careers
Dad shouldn't do the dishes this Sunday. But one study suggests that fathers who handle their fair share of household chores raise daughters who aspire to careers beyond those that are stereotypically female, such as nursing and teaching.
The strongest predictor of girls' career goals and attitudes toward traditional gender roles was whether their fathers did or didn't pull their weight around the house, noted the study, published in May in Psychologial Science.
Co-author Alyssa Croft, of the University of British Columbia, says she found the dads didn't necessarily tell their daughters to think past stereotypes—they showed it by taking on household tasks.
"It's important to not only talk the talk when it comes to gender equality at home, but walk the walk, because daughters seem to be watching." (Also see "7 Things You Don't Know About Mother's Day's Dark History.")
Story Time Success
Fathers are famous for their bedtime stories. Turns out these tales may play a huge role in raising successful kids, according to a study published earlier this year in the Journal of Applied Developmental Psychology.
In the experiments, parents read wordless picture books with their children so that scientists could analyze each parent's mean length of utterance (MLU)—a linguistic benchmark that increases when speakers use longer sentences and fuller descriptions.
They found that all parents who told stories with higher MLUs had kindergartners with bigger vocabularies and higher test scores. Dads in particular had an impact on their kids' development that went "above and beyond" moms, the study found.
The "findings highlight the unique contribution of fathers to children's early academic achievement," wrote co-author Claire Baker, an educational psychologist at the University of North Carolina. (Also see "Father's Day Shortchanged? Humble History, Fewer Gifts.")
Genetically, We're More Like Dad Than Mom
Mice, and likely humans, are more genetically similar to their fathers than to their mothers, according to a study published in March in Nature Genetics. We inherit DNA (nearly) equally from each parent but actually "use" more of dad's genes, the research suggests.
Researchers measured how genes are expressed—or how DNA is translated into proteins that guide the function of cells—for several types of tissues, including the brain.
For each gene, the team then quantified how much of this cellular process was derived from each parent. Across the genome, they found genes were expressed in a way that was significantly more like that of the fathers.
The work could help scientists unravel how ailments like diabetes or heart disease develop—and aid efforts to fight them.
"Imagine that a certain kind of mutation is bad," study author Fernando Pardo-Manuel de Villena, of the University of North Carolina School of Medicine, noted in a statement.
"If inherited from the mother, the gene wouldn't be expressed as much as it would be if it were inherited from the father. So, the same bad mutation would have different consequences in disease if it were inherited from the mother or from the father."
Roughhousing Builds Life Skills
Don't tell the kids, but rough-and-tumble playtime is a great learning experience. Many studies have explored how fathers that engage in creative roughhousing help kids evaluate risk, solve problems, learn their limits, manage excitement and aggression, and read others' emotional cues while conveying their own—all in a safe environment where nobody gets hurt.
"You can get it other places, but this is a particularly efficient way to learn," says Richard Fletcher of the University of Newcastle in Australia, who developed a guideline for how to measure the quality of rough-and-tumble play.
"It really is a fantastically complex constellation of emotions and self-regulation, which we now understand is a key element for children to develop well," Fletcher says.
Dads' Diets Influence Kid Health
Expectant mothers need to watch what they eat, but surprising research suggests that dad's diet also influences his future children's health.
In experiments, male mice with insufficient folate, or Vitamin B9, in their diets produced offspring with nearly 30 percent more birth defects—such as spinal and cranial deformities—than mice with sufficient folate, according to a study published in 2013 in Nature Communications. (Related: "Mice Inherit the Fears of Their Fathers.")
It's already known that folate protects against miscarriages and birth defects in the mother's diet.
Now, "our research suggests that fathers need to think about what they put in their mouths, what they smoke and what they drink," McGill University's Sarah Kimmins said in a statement, "and remember they are caretakers of generations to come."