29 C.F.R. § 1625.4

(a) Help wanted notices or advertisements may not contain terms and phrases that limit or deter the employment of older individuals. Notices or advertisements that contain terms such as age 25 to 35, young, college student, recent college graduate, boy, girl, or others of a similar nature violate the Act unless one of the statutory exceptions applies. Employers may post help wanted notices or advertisements expressing a preference for older individuals with terms such as over age 60, retirees, or supplement your pension.

(b) Help wanted notices or advertisements that ask applicants to disclose or state their age do not, in themselves, violate the Act. But because asking applicants to state their age may tend to deter older individuals from applying, or otherwise indicate discrimination against older individuals, employment notices or advertisements that include such requests will be closely scrutinized to assure that the requests were made for a lawful purpose.