Parental Cigarette Smoke Exposure and Its Impact on Offspring Reproductive Health: A Systematic Review of Maternal, Paternal, and Dual-Smoking Effects

The aim of this systematic review was to evaluate the impact of maternal, paternal and dual-parental cigarette smoke exposure on offspring reproductive health. Original human clinical and animal research studies were included; titles and abstracts were manually scanned for relevance to the effect of parental smoking on offspring’s reproductive outcomes (Date of search:18/03/2025). This systematic review incorporates 31 studies identified from three databases (PubMed, Web of Science, and Scopus). The results indicate that male offspring exhibit reduced spermatogenic capacity, characterised by decreased testicular size, lower sperm count, and impaired hormonal biosynthesis, with reductions of 30–40% in sperm production. Dual-parental smoking exacerbates these effects, with sperm counts averaging 85 million per ml in human male offspring from dual-smoking households compared to 111 million per ml in single-smoking households. Animal studies provide mechanistic insights, revealing reduced testis weight in nicotine-exposed male rats and increased oxidative stress in offspring. This review highlights the dose-dependent and sex-specific effects of smoking on fertility of the offspring and underscores the need for standardised protocols to enhance the consistency and comparability of future research in both human and animal studies.