Figure 1. Blood of aged males increases the ovarian follicle reserve in adult females. Non-atretic and atretic immature follicle numbers in ovaries of control (non-parabiotic) YF mice or YF mice 5 weeks after parabiosis with YF, YM or AM mice. Data are the mean ± SEM (n = 3-4 mice per group; *, P < 0.05).