Concerns about infertility are increasing worldwide. Infertility is estimated to affect 1 in 6 couples in developed industrialized countries with an almost equal contribution of male or female to the number of cases. Underlying causes of infertility associated with modern lifestyle are maternal ageing, obesity and diabetes, anxiety, alcohol consumption, smoking, and exposure to pollutants, including those acting as endocrine disruptors. All of these conditions promote excessive production of reactive oxygen species (ROS) that, when cellular antioxidant capacity is insufficient or ineffective, results in oxidative stress (OS). OS is believed to contribute to infertility by interfering with fundamental processes involved in reproduction, including spermatogenesis, folliculogenesis, fertilization, implantation, and placentation. At the subcellular level, excessive ROS dysregulate tissue-specific signalling pathways and promote oxidation of DNA, lipids, and proteins. In tissues of both male and female reproductive system, ROS has been shown to mediate induction of endoplasmatic reticulum stress with activation of unfolded protein response and/or cellular senescence, ultimately leading to cellular dysfunction and infertility. Thus, studies focusing on the causal connections between ROS, infertility, reproductive ageing, pregnancy-related pathologies, and cellular stress are of main interest.

In this Special Issue, we invite researchers to contribute with original articles aiming to highlight and unravel mechanisms by which OS contributes to infertility either of male or female origin and new pharmacological approaches that may target OS and improve fertility. Review articles addressing the role of OS on infertility and infertility-related pathologies are also welcome.

Potential topics include but are not limited to the following:

• In vitro and in vivo studies on the role of OS in infertility
• Inflammation, fibrosis, OS, and infertility
• Disruption of redox signalling, endoplasmatic reticulum stress, senescence, and infertility
• Proteostasis and infertility
• Dysfunction of mitochondrial dynamics and infertility
• ROS, obesity, and infertility
• ROS, reproductive ageing, and infertility
• Nutritional modulation of OS in a fertility promotion context
• Novel mechanisms and therapeutic strategies to improve fertility