The majority of the men in the sample (384 biological fathers and 80 social fathers) believed that their physical and/or verbal abuse of their spouses/partners negatively affected the children in the home, and the men expressed concern about the long-term effects on the children of witnessing the abuse. There was some support for the hypothesis that biological fathers would be more likely than social fathers to report that they had observed negative effects of their partner abuse on the children. There was also support for a second hypothesis that biological fathers would be more likely to worry about the long-term effects of their abuse on their children, particularly on girls. The study also found that biological fathers were more likely than social fathers to report that partner abuse negatively affected their partner's ability to parent effectively. There was no support for the hypothesis that biological fathers would be more likely than social fathers to report that they would stop their violence, seek professional help, or take other protective actions if they saw that their abuse was harming their children. Data were collected from 1,182 men, 18-63 years old, who were enrolled in a convenience sample of 37 United States and Canadian batterer intervention programs between 2002 and 2003. Of the surveys completed, 464 met the criteria for inclusion in this analysis. The 34-item survey questionnaire focused on fatherhood status, beliefs about the effects of intimate partner violence (IPV) on children, participants' feelings about the long-term effects of their children witnessing IPV, beliefs about the effects of IPV on coparenting interactions, actions the men would take to stop their violence, and demographics. 3 tables and 30 references