Armin answers: You are -- although it's not hard to understand where your friend got her information. Just about every scientific study done on attachment and bonding has focused on mothers and their children. But over the past ten years or so a few researchers have begun taking a look at father-child attachment. What they're finding isn't really that much of a surprise. In fact, it's what just about any man you know would tell you: the father-child bond is just as important as the mother-child bond.
For six-month old babies, for example, the more actively involved the fathers are, the higher the babies score on mental and motor development tests. Babies whose dads do a lot of basic, mundane childcare activities such as feeding, changing diapers, giving baths, and dressing, handle stressful situations better than babies whose dads aren't as involved. Some researchers have linked high levels of father involvement with higher math scores later on in school and to generally higher than age-level scores on verbal intelligence tests. And active fathering seems to be positively correlated with children's increased social adjustment and competence, and to higher levels of self esteem.
The bottom line is that children who live with involved, sensitive, and responsible fathers are better off than kids whose don't. They get along better with their peers, stay in school longer and do better while they're there, are less likely to abuse drugs or alcohol or to get pregnant (or get someone else pregnant) while in their teens, and they grow up to be more caring and sensitive adults.
Women, too, benefit from father involvement. Division of labor issues are the number one marital stressor, and the more support mothers get from their husbands, the less depressed they are, the happier they are in their marriages, and the better they perform their parenting duties. Finally, men themselves benefit from their own increased involvement with their families and children. Involved fathers tend to be more "generative" (giving, nurturing, and helpful), more occupationally mobile, more successful in their careers, and more likely to choose jobs that are people-oriented. In addition, men whose wives are happy in their marriages tend to be happier themselves. And men who are happy in their marriages are generally more involved in their fathering role.