ARE MEN CARRYING THE APOLIPOPROTEIN EPSILON-4-ALLELE OR EPSILON-2-ALLELE LESS FERTILE THAN EPSILON-3-EPSILON-3 GENOTYPES

The epsilon 3 allele in the human gene coding for apolipoprotein E (ap oE) is the most common worldwide, but epsilon 4 is probably the ancest ral allele. Since apoE is involved in many important biological proces ses, selection forces could have favoured epsilon 3. We hypothesized t hat apoE genotypes may affect reproductive efficiency, and we therefor e compared the distributions of 40-year-old married men with known gen otypes by the numbers of their biological children. The distributions were statistically significantly different (P = 0.0026). On average, m en with the epsilon 3 epsilon 3 genotype (n = 212) had 1.93 children, men with the epsilon 3 epsilon 4 or epsilon 4 epsilon 4 genotype (n = 105) had 1.50, and men with the epsilon 3 epsilon 2 or epsilon 2 epsil on 2 genotypes (n = 53) had 1.66 children. Of the men in the three gro ups, 6%, 26% and 19%, respectively, reported being childless. These fi ndings are unlikely to be due to gross error in the reported prevalenc e of childlessness, differences in socioeconomic status or other likel y sources of bias. They are compatible with higher fertility in men wi th the epsilon 3 epsilon 3 genotype than in those with the other commo n apoE genotypes.