Father's day, mother's day -- how about co-parents day?

"There's a Mother's Day and there's a Father's Day. But there's no Co-Parents Day," which should be celebrated, too, said Philip Cowan, a UC Berkeley psychologist and one of four principal investigators in the "Supporting Father Involvement Project," which is funded by the California Office of Child Abuse Prevention.

Using randomized clinical trials and couples group interventions, Cowan and his wife, Carolyn Pape Cowan, also a UC Berkeley psychologist, have been working with men and women to help them "be the kind of spouses and parents they want to be" for more than 30 years. Preliminary data from their latest longitudinal study on father involvement underscores the benefits of two-parent families, regardless of gender or marital status.

The Cowans said a second parent doesn't have to be a dad. It can be a same-sex partner, a grandparent or another caregiver.

"The point is to have two adults who are positively engaged with the child," said Philip Cowan, who, along with Carolyn, retired from teaching at UC Berkeley in 2005, though the pair continues to be active in family research. Other partners in the supporting fathers effort include Marsha Kline Pruett, a clinical psychologist and parenting expert, and Kyle Pruett, a psychiatrist who specializes in work with fathers.

In its eighth year, the study is now tracking the progress of some 300 low-income parents, many of whom have come into contact with child welfare systems in Contra Costa, San Luis Obispo, Santa Cruz, Tulare and Yuba counties. For 16 weeks, participants meet weekly with a group of other couples or parents and share with them stories and conflicts that come up in their personal lives and workplaces. The session leaders are trained in marriage or family therapy and are skilled at defusing arguments before they get heated, Cowan said.

The researchers follow up with participants for years to see how their relationships are going, and how their kids are doing socially and academically. That data is compared to that of a control group whose members attended a one-time presentation on the importance of father involvement in children's lives, but received no special help in a group intervention.

Early findings show that, compared to the control group, couples who completed the 16-week program are reporting higher satisfaction in their marriages or partnerships and their kids are doing better in school: "In each of our studies, we keep finding that the relationship between parents has a lot to do with how kids do in the long run," said Pape Cowan.

And many graduates of the program can vouch for that finding:

"Kids need both parents. They need to know that both parents love them," said Reginald Johnson, 39, of Richmond, who has sole custody of his 2-year-old son while the boy's mother completes a court-mandated substance abuse program.

Johnson said the program helped him let go of his anger at not being raised by his biological father, and about the drug addiction his baby was born with. But the most important thing he learned was that, for the sake of his child, he needed to communicate better with his son's mother.

"I talk to her. I write to her. I want my son to have a bond with his mom," Johnson said.

Andre White, 46, a musician who just completed the Supporting Father Involvement Project in San Luis Obispo County, is another convert to the benefits of talking through parenting conflicts instead of blowing up, and of sharing the load with his spouse.

"These days, both moms and dads are working, so you can't say it's just one person's job to raise the kids. You've got to do it together," said White, who is active in Head Start and other family support programs. He and his wife, Brenda, are raising their 9-month-old granddaughter and 4-year-old grandson.

White fondly remembers a breakout session in which the fathers and the kids went into a room, rolled around on the floor and had a balloon fight. They then made paper cutouts of themselves by tracing their outlines, and placed the cutouts of their kids inside their own.

"It was really cool," White said. "I didn't want those classes to end."

Pape Cowan said many participants in the program find it a relief that they're not alone in their problems: "They're looking around and thinking, 'It's not just us having trouble'," she said.

Once dads start to grasp how important they are to their children, their patterns change, she said. For example, one father reported that he started going to his child's school during the lunch hour to read to him. Another reported that he now asks his 5-year-old daughter to join him on errands instead of going by himself.

"A lot of these people have really hard lives, so it's emotionally rewarding to hear that they're making these positive changes." Pape Cowan said.

Philip Cowan noted that not all social service agencies are father-friendly and a perceived snub can quickly turn fathers off from seeking help. However, he said, once fathers feel welcomed, they can be surprisingly perceptive about how to be a more effective parent.

"Once they're in the door, they're as interested as the moms," Cowan said.

Since 1980, the Cowans have tracked more than 1,000 families in three longitudinal studies. Their first study, the "Becoming a Family Project," helped working and middle class couples get ready for the birth of their first child. The Cowans followed up with the new parents for five years and found that those who took part in the couples groups enjoyed more marital and parental satisfaction than control group members who received no counseling.

Their next study, the "Schoolchildren and Their Families Project," offered weekly couples groups before the families' first children entered kindergarten. Those sessions helped reduce conflict and behavioral issues related to the transition to kindergarten, and the project earned the Cowans an award from the American Family Therapy Academy.

The Cowans recommended that single parents also take part in support groups and forge bonds with other families.

Johnson, the single dad from Richmond, recalled feeling shy sharing his problems with a room full of strangers when he was first in the program, and isolated as a parent. But as time went on, he said, those strangers became friends with whom he now regularly meets up so their kids can play together.

He recently spoke to an audience of 200 Contra Costa county staff members in Concord, Calif., about how the program has helped him improve his communication skills and form bonds.

"I never used to feel comfortable talking about myself, "he said. "But that class helped me express myself and open up to people. It helped me be a better father."