In settings where marriage and childbearing are tightly linked, marriage is a prerequisite for having children. Women take on more home care duties after marriage, and their labor market outcomes often begin to shift even before a first birth. If changes in women's work are put down to childbearing alone—overlooking the gendered redivision of labor that marriage itself brings—the total family formation penalty will be seriously underestimated. Using CFPS data, this paper adopts a joint event study design built around first marriage and first childbirth. It estimates recent marriage, childbearing, and family penalties on women's work for those first married between 2010 and 2022, uses Oaxaca decomposition methods to gauge how much these penalties add to the gender gap in work, and asks whether they arise from a gendered split of home labor rooted in social norms.

Key findings are as follows. First, Chinese women face a 17.4% marriage penalty and a 16.2% child penalty, yielding a total family penalty of 33.6%; both contribute almost equally to women's work losses, yet the child penalty is larger in the short run. Second, standard single-event studies typically leave out the marriage penalty and thus underrate the harm family formation inflicts on women's work. Third, the family penalty makes up 74.1% of the 2020 gender gap in paid work, and the child penalty's share of this gap has risen over time. Fourth, these penalties persist even when women have no less schooling than men. Long-held gender norms keep driving how home roles are split, which is very likely the main reason women end up with a larger family penalty.

The paper adds to the field as follows. First, by turning seven waves of CFPS cross-sections into panel data via personal IDs and a joint event study design, it pins down both the marriage and child penalty for Chinese women. Second, for cases with no pre-marriage data, it uses pseudo-event study matching on sex, age, year, schooling, and urban/rural status (or province) to enlarge the sample and run robustness checks. Third, mechanism analysis further shows the old gendered split of home labor is the main path through which both penalties operate. No matter how spouses' pre-marriage edges stack up, women's housework time rises sharply after marriage versus men's, strongly hinting that old social norms may lie at the root of gender gaps in China today.

These empirical results point to several clear and actionable policy steps. First, formally recognizing domestic services and offering subsidies for their use can transform gendered unpaid care into paid services that families can readily purchase. Second, introducing a dad-only, non-transferable paid parental leave would send a strong and clear signal that care is a joint responsibility, thereby helping to break the deeply entrenched image of women as sole carers. Third, establishing an inclusive child care system based on full-day care with extended-hour add-ons can ease family care burdens and enable both parents to participate more fully in paid employment.