Why Men Are Typically Taller Than Women

While studying genetic factors behind different traits in men and women, University of Helsinki researchers have identified a genetic variant on the X sex chromosome that accounts for height differences between the sexes. Sex cells, produced by male and female gonads, contain either an X or a Y chromosome. The fact that females have two X chromosomes and males only have one X chromosome must be taken into account when attributing difference in traits to variants on the X chromosome.

According to the study's head researcher, Professor Samuli Ripatti, "The double dose of X-chromosomal genes in women could cause problems during the development. To prevent this, there is a process by which one of the two copies of the X chromosome present in the cell is silenced. When we realized that the height associated variant we identified was nearby a gene that is able to escape the silencing we were particularly excited." The height variant identified influences a gene that is involved in cartilage development. Individuals that possess the height variant tend to be shorter than average. Since women have two copies of the X chromosome variant, they tend to be shorter than men.

Learn more about this study:

• Opening 'the X-Files' Helped Researchers to Understand Why Women and Men Differ in Height (Science Daily)