Fathers' Imprisonment and Mothers' Multiple-Partner Fertility

Background/Purpose:This research brings together two striking trends: dramatic increases in the incarceration of fathers and steady increases in the proportion of mothers who have children with more than one partner (multiple-partner fertility, or MPF). Fathers’ imprisonment may increase mothers’ MPF because imprisonment immediately enforces couples’ separation and breaks bonds, even after release. Mothers’ MPF increases the complexity of children’s family relationships and affects their well-being. A few studies have included paternal incarceration as a control variable and found higher rates of MPF when a father was incarcerated (Carlson, 2006; Logan, Manlove, & Ikramullah, 2006), but none of these studies has focused on whether the relationship is causal. Our focus is whether paternal imprisonment leads to MPF. 

Methods:

Data, sampling, measures:  Matched longitudinal administrative data were drawn from Wisconsin’s child support, prison, employment, and public assistance records. Previous research suggests child support records provide very good measures of MPF and its timing. We examine a representative sample of 6,032 children, which includes approximately 10% of unmarried mothers’ firstborn children born 1998-2002.  For these children, we document their mothers’ fertility over the first six years of the children’s lives and model how it relates to the imprisonment of their fathers.  We create monthly binary measures of fathers’ imprisonment. As for the dependent variable, we measure the occurrence and timing of the mother’s second birth. Control variables include demographic and socio-economic characteristics of both parents (age, race, time-varying measures of earnings and public assistance program participation).

 Analytic/statistical approach:  To examine the relationships between paternal imprisonment and the timing of the mother’s second birth, distinguishing between a birth to the same father and a birth to a different father (MPF), we employ multinomial logistic (MNL) competing-risks models. However, concerns remain about unobserved differences between mothers who did and did not experience partner imprisonment in the interpretation of MNL results as a causal relationship. To help identify the causal relationship between partner imprisonment and mother’s MPF, we also employ the case-time-control method, a fixed-effects method for the analysis of non-repeated events.

Results:  Within a child’s first six years, 23% experience their mother’s MPF. Our results demonstrate that first-partner’s imprisonment increases the likelihood of a mother’s MPF and decreases the likelihood of any additional births with the same father, relative to remaining single. The MNL model shows that mothers who experience partner imprisonment are 17% more likely to have MPF, relative to remaining single. We found consistent results from the case-time-control analysis (fixed-effects analysis), supporting the interpretation of a causal relationship between the father’s imprisonment and the mother’s MPF.

Conclusions and Implications: Our findings have implications for incarceration/diversion programs, prisoner re-entry programs, and marriage and parenting programs. Further research on other effects of incarceration and the effects of MPF on various aspects of child well-being could build on this work.