This study used photo (stimulus persons) to explore age categorization in a sample of 150 subjects of diverse ages: 15 males and 15 females in each of five age groups: 18--21, 22--28, 29--38, 39--55, and 56--76. Two sets of 33 photos each (a male and a female set) were presented to subjects for chronological age estimation, age categorization (as adolescent, young, middle-aged, elderly, and aged adult), and preference. Results indicated considerable overlapping of estimated ages across age categories, suggesting that the boundaries between adjacent age stages are highly permeable. Sex-of-photo exerted a major influence on categorization and preference. Female, relative to male, stimulus persons were assigned to older age categories, were perceived to attain middle-aged and elderly status sooner, and were younger when chosen as most preferred (but only for male subjects). These sex-bias effects were mitigated in the oldest respondent. Relevance of the present research to problems of age stereotyping is discussed.