This paper studies the effects of vehicle ownership restrictions on fertility. We examine Beijing's license plate lottery system, which began in 2011 and restricts the number of new and used vehicles people can obtain. Leveraging a randomized survey, we show that one unintended consequence of the vehicle restrictions has been to reduce the number of births in the households of lottery entrants between 2011 and 2014. The vehicle restrictions reduce births in households of lottery participants by 35 percent, implying a remarkable 6 percent reduction in births across the entire city. We report changes in household structure and age composition consistent with this change in births.