When it comes to spanking children, reading to them, or showing affection, mothers are strongly influenced by the way their own moms acted — but dads aren’t. That’s the finding of study that followed two generations of parents, starting in the late 1970s, and checked up on moms’ and dads’ parenting practices through the years. Women whose mothers had read to them a lot were more likely to read to their own children, and the same pattern held for praising children, showing affection, and spanking. Men’s habits, however, seemed more or less unrelated to how they were treated by their moms. The sole exception was spanking: Men who had been spanked as a child were in fact less likely to spank their own kids.

The results were somewhat surprising to the Ohio State University researchers who analyzed the data, and who presented their findings this past weekend at the annual meeting of the American Sociological Association. “These fathers were growing up in ’70s and ’80s and received much of their parenting from their mothers,” said co-author Jonathan Vespa in a statement. “There was good reason to expect that fathers would have learned parenting from their mothers.”

So where did these dads pick up parenting skills? It’s not clear. Fathers may adopt practices from their dads instead of their moms, or from their wives, or from someone else entirely. This study can’t answer the question because the second-generation participants were all children of the first-generation women, and not of the first-generation men (who were married to other women, not participating in the study). Simply put, researchers had data about moms’ influence on kids of both sexes, but no data about dads’ influence on either.

Of course parenting habits have changed plenty in the past 30 years — and family tradition is just one influence among many. Irrespective of their moms’ approach, for example, current-generation parents tend to be more affectionate with kids and less likely to spank. They’re also much more likely to read to kids than their own parents were — about three times as likely. Only time will tell, it seems, which practices are habits for the generations.