Do lunar phases influence semen parameters?

Objective. The aim of this retrospective study was to analyze semen parameters of a large group of individuals during a lunar cycle. Material and methods. We analyzed the semen parameters of a continuous series of 386 male patients by optical microscope according to WHO guidelines. Data were grouped according to the four primary phases of the moon: the new moon (nm), the first quarter (fq), the full moon (fm) and the last quarter (lq) and the values were statistically compared. Results. This study failed to show any statistically significant difference in semen parameters during the four lunar phases. Nevertheless, the median value of semen volume during the full moon phase showed a trend towards lower values (3.3 ± 1.57) compared to the median values observed during the other phases of the moon (nm, 3.67 ± 1.66; fq, 3.52 ± 1.8; lq, 3.45 ± 1.86) as well as the frequency of increased viscosity was very reduced during the new moon phase (15.53) compared to the other phases (fq, 26.25; fm, 26.47; lq, 22.77). Conclusions. Lunar cycle seems do not affect semen parameters. A large study considering semen samples from the same patient for each lunar phase should be set up in order to better clarify whether lunar rhythm could influence male fertility.