A focused evaluation of genetic and epigenetic contributions to common infertility conditions.

Infertility is a complex condition influenced by genetic and biological factors. In men, it is often caused by abnormalities in chromosome number or structure, alterations in DNA structure, specific gene mutations, or missing segments of the Y chromosome. Recent studies have also highlighted the impact of epigenetic mechanisms-such as DNA methylation, histone modifications, and noncoding RNAs-on gene function and fertility. Abnormal methylation patterns, particularly in genes such as DNMT3A/B/L, H19, MEST, SOX30, and those involved in the piRNA pathway, have been linked to poor sperm production and reduced fertility. These epigenetic changes can lower sperm quality, impair embryo health, and decrease the chances of success with fertility treatments. The role of biological and epigenetic factors in female reproduction is more limited. This narrative review aims to examine well-established genetic and epigenetic mechanisms associated with infertility, with a focus on key molecular pathways and regulatory processes. A literature review was conducted to summarize the most relevant and recent publications addressing genetic and epigenetic mechanisms as contributing factors to human infertility.