Aging is characterized by a progressive decline of tissue organization and function that correlates with chronological age. The link between aging, progeny production, and reproductive decline, however, is controversial. Antagonistic pleiotropy was proposed in the 1950s and theorized that extending life span required a reduction in progeny production, and vice versa. Consistent with this theory, loss- or reduction-of-function mutations in insulin signaling, mitochondrial electron transport, or caloric intake extend life span and often reduce progeny production in a number of organisms. However, the effects of increasing progeny production on life span have not been adequately investigated. To address this, we conducted longitudinal studies using C. elegans N2 hermaphrodites mated to N2 males, and we analyzed brood size, reproductive span, fast body movement span, pharyngeal pumping span, and life span. In addition, hermaphrodites were unmated or mated to sterile fer-6(hc6) males-these animals mate but do not transfer viable sperm. The brood sizes and reproductive spans of mated hermaphrodites were nearly double those of unmated or fer-6(nc6) mated hermaphrodites. We also observed that the fast body movement, pharyngeal pumping, and life spans did not significantly differ among unmated hermaphrodites or those mated to N2 males or fer-6(hc6) males. These data suggest that doubling brood size and extending the reproductive period does not decrease life span, contrary to the predictions of antagonistic pleiotropy. Additionally, our preliminary data suggest that different E. coli strains can increase cross brood size. Animals grown on HT115 have larger cross brood sizes than those grown on OP50. We draw two conclusions from these data. First, animals grown on OP50 are not maximizing their reproductive potential. Second, brood size and life span are not involved in a trade-off in hermaphrodites grown on food that does not maximize their reproductive potential. We are currently testing other bacterial strains and species to determine the maximal level of cross progeny production and the effect on life span. Furthermore, in order to analyze reproduction and life span in C. elegans populations, we are validating a liquid culture system where we control food, predation, and the environment.