Over the last 20 years we have witnessed a decrease in the birth rate, also due to a decline in fertility, as demography shows. In fact, an increase in the percentage of aging is estimated by 2050 worldwide. According to the data, one in five couples cannot procreate naturally. The reasons could be many, but, among these, it affects a lot than in the last 30 years, the average age of conception in both sexes has increased by almost 10 years and lifestyles have changed to the point of damaging fertility.

Often, mistakenly, infertility problems tend to be associated more with women, while in reality they depend on both, about 40% of the causes of infertility mainly concern the female component, the other 40% concerns the male component and a 20% instead it is of a mixed nature.

A good share of the cases of male infertility they are classified as idiopathic, i.e. without apparent cause, there is no explanation. One of the best known and most widespread diagnoses is azoospermia, that is, the absence of spermatozoa in the seminal fluid; oligospermia which instead consists in the reduction of the number of spermatozoa or, also asthenospermia which is characterized by reduced sperm motility. There could also be other causes linked to any abnormalities in the morphology.

What can all this depend on? From errors during spermatogenesis, the sperm production process; from problems during cell divisions, or during the formation of the male gonads and related glands, but also from pathologies affecting the reproductive system, and the genetic component is not excluded.

What is meant by genetic component? It means the set of genetic factors that can influence a specific character. In this regard, numerous studies have been carried out to demonstrate that genes play a key role in infertility. In a recent study, have been compared approx 185 infertile patients with their unaffected parents, in order to check that there was no transmission from the parents. Following an analysis, they were found "de novo" mutations, that is, mutations present for the first time in patients and totally absent in the genetic set of the parents, which have not been inherited but are the result of a new event that could be passed on to the offspring.

Some of these mutations have altered rare proteins that have been classified as possibly responsible for the diagnosis of infertility, because many of these genes had lost their function. In particular, in infertile patients, the authors have identified alterations in a gene that regulates the maturation of the messenger RNA of male germ cells, while in healthy controls they were not present.

Those results obtained indicate new candidate genes that influence fertility. This, in the future, will improve the diagnostic performance and help to better understand the possibilities of transmission to couples seeking treatment.