"Many of these men do want to take responsibility for their children," Dr. Randall Leite, of Bowling Green State University in Bowling Green, Ohio, said in a statement. "There are things preventing that from happening."

Barriers to fatherhood include: low-paying jobs or unemployment; medical providers who leave the fathers feeling left out; maternal grandparents, and especially grandmothers, whose involvement may discourage the fathers; and troubled relationships with the mothers of their children, according to the quarterly journal Family Relations.

"When you look at what would help these men, programs to enhance the co-parenting relationship with the mother are probably the most important," Leite said.

Leite also sees a need to address the role of the maternal grandmother and how she can complement the father. Many people think grandmothers are more involved because dads aren't, but many men in Leite's research said they weren't involved because the grandmother was -- an example of "boundary ambiguity."