depending on the system chosen by the state. Most military personnel are males; the minority proportion of female personnel varies internationally (approximately 3% in India, 10% in the UK, 13% in Sweden, 16% in the US, and 27% in South Africa). While two-thirds of states now recruit or conscript only adults, as of 2017 50 states still relied partly on children under the age of 18 (usually aged 16 or 17) to staff their armed forces.

Whereas recruits who join as officers tend to be upwardly-mobile,