Duration of sexual arousal predicts semen parameters for masturbatory ejaculates

Intelligence and semen quality are positively correlated

“…We extracted a principal axis factor (unrotated) from the three semen measures to see whether this improved the reliability of the measures, but the correlation with g was very similar (r = .17). Semen quality varies across ejaculates not just according to days abstinence, but also by collection method (Gerris, 1999;Pellestor, Girardet, & Andreo, 1994), and psychological context (such as cues of partner infidelity (Baker & Bellis, 1989;Kilgallon & Simmons, 2005;Pound, Javed, Ruberto, Shaikh, & Del Valle, 2002). Thus, each man's single ejaculate as measured in this study is an imperfectly reliable indicator of his average semen quality across actual copulations.…”

Individual Variation in Semen Parameters of Healthy Young Volunteers

“…There have thus been several studies of intra-individual variation in semen characteristics that have mentioned the need for caution with regard to intraindividual variation, but no one has conducted a comprehensive study of semen characteristics overall in healthy volunteers of virtually the same age over a relatively short period as we did in our study. Stress [9,21], temperature [1,19], diet [10,25], drug intake [7], age [13,14], period of abstinence [22], seasonal variation [17], and air pollution [26,29] have previously been put forward as factors that may affect semen characteristics in humans. Many factors may therefore affect semen characteristics and it is difficult to determine the effect of any one of these factors specifically.…”

“…The results of semen analysis are also affected by the period of sexual abstinence [22], the sample collection site [4], individual variation [18,23], and seasonal variation [17]. The WHO Manual [28] shows a graph of changes in sperm concentration in the same individual over a two-year period.…”

Effect of Sample Collection Site on Semen Parameters of Healthy Young Volunteers

“…It is possible that as the period of abstinence becomes longer, more sperm are produced and the sperm concentration therefore increases [18]. When carrying out semen analysis, it is therefore recommended that patients be instructed to collect samples after the same period of abstinence so that the results can be compared [23,24].…”