Fig. 4
From: Association of the MTHFR 677C>T and 1298A>C polymorphisms and male infertility risk: a meta-analysis
Funnel plot for publication bias test [for 677C > T polymorphism: a for TC vs. CC, p = 0.281; b for TT + TC vs. CC, p = 0.196; for 1298A > C polymorphism: c for CC vs. AA, p = 0.403; d for CC vs. CA + AA, p = 0.235]. Each point represents a separate study for the indicated association. Log [or], natural logarithm of OR. Horizontal line, mean effect size