Percentage of headless sperm from cauda epididymides of WT (black), Spatc1l+/- (gray), and Spatc1l-/- (white) mice. The average percentage of headless sperm in WT, Spatc1l+/-, and Spatc1l-/- males was 6.3, 52.9 and 100, respectively. Each dot represents percentage of headless sperm in an individual mouse, and medians are represented as horizontal lines. (n=13, *P < 0.001, Student's t-test). 