Stepfather Investment and Reproductive Outcomes Among US Couples

Although paternal investment in humans is highly variable, many males invest heavily in offspring. Biological fathers invest more in children than stepfathers, yet stepfathers do invest in their stepchildren, possibly to gain mating access to the mother. Stepfathers are also more likely to be abusive and antagonistic towards their stepchildren than biological fathers. Most previous research quantifies the investment of stepfathers in relation to biological fathers. However, no studies have explored how investment and relationship quality influences reproductive outcomes for stepfathers. I examine how stepfathers’ relationship quality with stepchildren associates with stepfathers’ reproductive success (number of biological children born to the couple) by utilizing the National Survey of Families and Households longitudinal survey of American couples. I also examine how mother’s financial autonomy may moderate the relationship between investment and reproductive success. Results show some evidence that stepfather investment can improve reproductive success, but these results are not particularly strong and may be difficult to interpret.