This paper studies how fertility and children reshape couples’ relocation decisions and their gendered consequences for geographic job mobility, wages, and welfare. Using Australian panel data, I document that before children, both spouses’ preferences equally predict long-distance moves; after the first birth, husbands’ preferences dominate regardless of relative education and income, and the gender wage gap widens following relocation. To interpret these patterns, I develop a dynamic collective household model with endogenous fertility, joint job search, and bargaining over relocation under limited commitment, in which decision weights respond endogenously to spouses’ outside options. The model highlights two mechanisms: children raise the payoff to specialization and weaken the primary caregiver’s outside option, tilting decisions toward the male partner’s preferences and gains. I validate these mechanisms using a quasi-experimental design based on a 2015 reform to Australia’s Family Tax Benefit, which tightened eligibility for single-earner couples for a benefit paid directly to the non-working spouse. Estimates from the model show that fertility is a key margin shaping couples’ geographic job mobility and that bargaining frictions induce moves that disproportionately lower women’s wages and welfare. Eliminating this friction would not reduce aggregate mobility but would instead reallocate moves to those with more equal gains. Finally, I show that policies ignoring these internal dynamics—such as relocation subsidies—amplify within-household inequality, whereas family policies that strengthen women’s bargaining position—such as childcare subsidies—promote more equitable moves without sacrificing mobility.