title: The hard core.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D011203:Poverty; D011247:Pregnancy; D012940:Social Problems / Q000639:trends*; D012946:Social Welfare / Q000639:trends*; D014481:United States