Sparta’s population of full citizen-soldiers (Spartiates) was chronically small and constantly at risk of shrinking through war or disease. Marriage was viewed purely as a state breeding contract rather than a matter of romance. To reinforce this duty, the society rewarded men who had large families (such as being exempted from military service or taxes if they had three or four sons) while treating bachelors as social outcasts.
. . .
According to the historian Plutarch, unmarried men (agamoi) faced strict public humiliation every winter to shame them into compliance…
In the freezing cold of winter, officials forced unmarried men to march in circles around the public marketplace (agora) completely naked. As they walked, they had to sing a self-mocking song or a specific derogatory tune written about themselves, publicly confessing that they were justly punished for disobeying the laws.
Bachelors were stripped of certain honors and citizen rights. Younger men were also permitted and even expected—to disrespect or withhold the customary signs of deference that older men normally received, such as yielding seats or standing up for them. Furthermore, they were banned from attending the sacred athletic and religious dances of the Gymnopaedia festival.