Table 1.

Results from mixed model investigating the effect of male and sperm age on sperm number and sperm swimming velocity. (Young male and fresh sperm are reference groups for the estimates. Significant p-values are reported in italics.)

	sperm number			sperm velocity
	estimate (s.e.)	F	p	estimate (s.e.)	F	p
male age	−0.3279 (0.492)	6.162	0.014	−7.778 (2.207)	9.221	0.003
sperm age	4.6650 (0.423)	163.918	<0.001	−13.890 (1.933)	49.460	<0.001
male age × sperm age	−1.0790 (0.678)	2.519	0.115	6.053 (3.089)	3.839	0.052