Changes in the composition of the work force and changing work values require new life span and career development models that account for individual, gender, and cultural differences in experience. Age/stage models form one school of thought in developmental theory. A major criticism of prevailing theories is that they are based on male experiences. Researchers are questioning the validity of age-linked phases. Schlossberg's more eclectic approach of viewing the adult experience may be more useful in explaining different life/career experiences. The criticisms of existing models point out elements that are needed in revised theories of human development: redefining maturity; importance of attachment; integration of independent and interdependent aspects; relationship elements--the interweaving of the individual, family, and work; charting patterns of productive activity and relationships with others over a time span to reveal life patterns--parallel, steady/fluctuating, and divergent; developing a profile of a generation or cohort based on social, historical, and cultural factors; and cycles of stability and change. (13 references) (NLA)