['To investigate the effects of kidney-jing deficiency on the fertility of male mice and their male offspring.', 'Thirty 6-week-old Kunming male mice and 300 female ones were randomly allocated to a blank control group, a model group and a kidney-tonifying group. The model and the kidney-tonifying groups were stressed by fear plus excessive sex to establish a kidney-jing deficiency model, and meanwhile the latter were given concentrated solution of Kidney-tonifying Recipe intragastrically at the dose of 0.16 ml/10 g. The control and the model groups were treated with physiological saline at the same dose for 21 days. Then all the male mice were mated with the healthy estrous females for 5 days. The sperm density and motility of each group of the male mice were examined, and their fertility was assessed by comparison of the pregnancy rate and the number of baby mice at each birth among their female mates. And the sperm density and motility of the male offspring were detected at 6 weeks.', 'The average number of baby mice at each birth in the model group was (7.00 +/- 1.73), significantly smaller than those in the control (9.43 +/- 1.27) and the kidney-tonifying group (8.80 +/- 1.10) (P < 0.05). The sperm density and motility of the model mice were (9.70 +/- 1.15) x 10(6) / ml and (66.72 +/- 10. 12) %, lower than those of the control ([14.08 +/- 1.15 x 10(6)/ ml and [81.75 +/- 3.56] %), and the kidney-tonifying group ([12.20 +/- 1.55] x 10(6)/ ml and [78.55 +/- 4.38] %) (P < 0.05). There was no significant difference between the latter two groups (P > 0.05). The sperm density and motility of the offspring of the model mice were (10.10 +/- 1.79) x 10(6)/ ml and (71.86 +/- 7.48) %, lower than those of the control ([15.30 +/- 1.83] x 10(6)/ ml and [79.86 +/- 5.68] %), and the kidney-tonifying group ([14.20 +/- 2.21] x 10(6)/ ml and [81.92 +/- 2.51] %) (P < 0.05), with no significant difference between the latter two groups (P > 0.05).'] Does [ Kidney-jing deficiency reduce the fertility of male mice and their male offspring ]?