A new research suggests men's susceptibility to serious health conditions are influenced by low exposure to testosterone in the womb.
Understanding why some men have less of the hormone than others is important because testosterone is crucial for life-long health. Low levels of the hormone have been linked to obesity, diabetes and heart disease.
Researchers have shown that the cells responsible for producing testosterone in adults - known as Leydig cells - are derived from a specific population of stem cells found in the testes.
The team found evidence of these stem cells in the developing testes of babies, rats, mice and marmosets in the womb.
Leydig cells do not develop until puberty but the team showed that their function is impaired if their stem cell forefathers are exposed to reduced levels of testosterone in the womb.