Infertility is the inability to achieve pregnancy after 12 or more months of regular and unprotected intercourse as defined by the World Health Organization (WHO). Male infertility is a complex disease caused by anatomical defects, injuries, endocrine disorders, immune system problems, genetic factors, and viruses. There are over 48.5 million couples worldwide who suffer from infertility. Additionally, it is estimated that there are more than 30 million infertile men globally. Despite the alarming prevalence, the causes of male infertility remain enigmatic in a large percentage of cases, this is why researchers have recently tried to study the epigenetic origin of male infertility. Epigenetic research focuses on changes in gene expression inherited through meiosis or mitosis without altering the DNA sequence. These modifications include histone modifications (a post-translational modification in histones that is very important in the proper functioning of cells. The N-terminal contains amino acids that can be used for methylation, acetylation, phosphorylation, and ubiquitylation of the receptor), DNA methylation (an essential epigenetic modification specifically related to gene silencing), chromatin remodeling, and RNA-based mechanisms (we can refer to changes in miRNA, mRNA, and piRNA).
