At what age must all men register for the Selective Service?

Men are required to register for the Selective Service at the age of 18. This registration is a legal requirement in the United States, ensuring that the government has information about potential conscripts should a military draft be reinstated. The significance of turning 18 is tied to when individuals reach adulthood in many respects, including the ability to vote and assume other legal responsibilities.

Registering at this age allows the Selective Service System to maintain an up-to-date list of eligible individuals who could be called upon in a time of national emergency or military need. Options such as 16, 21, or 25 do not align with current legal requirements for registration, as those ages either precede the age of majority or don't reflect the designated timeline set by the government for this responsibility.