Some of fathers’ contributions are surprising. One might guess, for example, that mothers have more influence than fathers on their children’s language development. Despite the growing number of women in the workforce, mothers still spend more time with children in many families than fathers do. But that turns out not to be the case. Lynne Vernon-Feagans of the University of North Carolina, who studies language development, has found that when it comes to vocabulary, fathers matter more than mothers.