The body of evidence about nuts and pregnancy and fertility continues to grow, with new local and international research papers regularly published.

Body of evidence

Hazelnut consumption improves testicular antioxidant function and semen quality in young and old male rats. (2019).
Hazelnut supplementation in the diets of young and old rats significantly improved testicular function and semen quality.

Maternal nut intake in pregnancy and child neuropsychological development up to 8 years old: a population-based cohort study in Spain. (2019).
In the first of its kind, a study led by the Barcelona Institute for Global Health found children, whose mothers ate more nuts during the first trimester of pregnancy, achieved the best results in tests measuring cognitive function, attention capacity and working memory.

Effect of nut consumption on erectile and sexual function in healthy males: A secondary outcome analysis of the FERTINUTS randomized controlled trial. (2019).
Compared to the control group, a significant increase in the orgasmic function (p-value = 0.037) and sexual desire (p-value = 0.040) was observed during the nut intervention. No significant differences in changes between groups were shown in peripheral concentrations of NO and E-selectin. Including nuts in a regular diet significantly improved auto-reported orgasmic function and sexual desire.

Effect of nut consumption on semen quality and functionality in healthy men consuming a Western-style diet: a randomized controlled trial. (2018).
Snacking on a handful of nuts can improve male fertility. The study demonstrated that men who snacked on nuts every day experienced significant improvement in sperm quality parameters. The RCT showed that these improvements resulted from consuming 60 grams per day of nuts (30g of walnuts, 15g of almonds and 15g of hazelnuts), compared to consuming no nuts.