PLOD1 and cryptorchidism: Compared with those who failed sperm production (N subgroup), the successful group (S subgroup) had a lower rate of cryptorchidism (25% vs 14%, P = 0.032, by χ2 test), larger basal testicular volume (1.8 ± 1.1 vs 2.3 ± 1.8 mL, P = 0.023, by independent t test) and higher peak LH level after triptorelin stimulation (Figure 3, Table 1).