Modern fertility techniques like flow cytometry allow parents to carry out preimplantation sex selection at low cost, no medical risk, and without the ethical or medical concerns associated with late abortions. Sex selection for non-medical purposes is legal in many high-income countries, and social norms toward assisted reproductive technology are increasingly permissive and may plausibly become increasingly prevalent in the near future. While concerns over son preference have been widely discussed, sex selection that favors female children is a more likely outcome in high-income countries. If sex selection is adopted, it may bias the sex ratio in a given population. Male-biased populations are likely to experience slower population growth, which limits the long-term viability of corresponding cultural norms. Conversely, female-biased populations are likely to experience faster population growth. Cultural norms that promote female-biased sex ratios are as a consequence therefore also self-reinforcing. In this study, they explore the demographic consequences of a female-biased sex ratio for population growth and population age structure. They also discuss the technology and parental preferences that may give rise to such a scenario.