<p>This paper investigates the optimal fertility strategy and its impact on the fertility rate and parental investment in a patriarchal society. Parents with son bias first make sequential fertility choices and then make parental investment decisions based on the realized sex composition of children. The optimal fertility strategy is a one-stage look-ahead strategy and represents a son-preferring stopping rule. I characterize the resulting population distribution of the possible sex combinations of children in a family, which shows that females are disproportionately born into larger families and, as a result, receive less investment than males, on average. In addition, both under- and over-reproduction occur in a patriarchal society, but the average fertility rate may be lower than in a gender-neutral society. Lastly, I show that the son-preferring stopping rule as the optimal strategy is robust to the introduction of sex selection and alternative investment options for a large set of parameters.</p>