The proposed research reexamines the relationship between welfare and children's living arrangements. Its focus, however, is neither marriage nor the formation of one-verse two adult households. Instead, it mirrors welfare eligibility rules more lolly than any previous study by focusing on the blood relationship between children and the adults they live with. The benefits of this precision are two-fold. The first is that, by being more accurate about the choices families face and about welfare's treatment of their choices, we improve measurement of the program's behavioral effects. The second is that we address welfare's impact on children along a dimension of newly emerging importance: the biological relationship between the child and the second adult in the household. The empirical portion of this research uses variation of welfare benifites across states and over time to measure responses to welfare's disparate treatment of fathers versus other men in children's homes. A key question to be answered is whether high we benefits raise the odds that a two-adult household with children contains an unrelated man instead of the children's father. The data consist of none years' worth of pooled cross sections from the Sense Bureau's Survey of Income and Program Participation (SIP). The roughly 100,000 observations on children permit the inclusion of state- and M.A.-level fixed effects along with many other state-level variables. To our knowledge, this is the first- ever study to exploit SIP's household relationship matrices.