Gender Imbalance: A situation where there is an unequal distribution of males and females in a population, which can lead to various social and demographic consequences.
Marriage Squeeze: When there are more potential brides than grooms (or vice versa) due to imbalanced sex ratios, making it difficult for some individuals to find suitable marriage partners.
Demographic Transition: The shift from high birth rates and death rates to low birth rates and death rates in a population over time, which can affect sex ratios as well as migration patterns.