A recent review study published in the American Journal of Stem Cells (AJSC) on May 15th, 2016, suggests that a father’s increasing age and an unhealthy lifestyle can result in the birth defects among offspring and their successive generations on a genetic level. The study, also covered by the British Medical Journal (BMJ) today, described an unhealthy lifestyle as one consisting of bad dietary habits, alcohol consumption and cigarette smoking.

The researchers reviewed epidemiological and laboratory studies, which focused on the mechanism responsible for changing the phenotype and behavior of the offspring. In addition to exploring possible links between birth defects and paternal age, the study also examined varied environmental and dietary factors. Results showed that changes are caused by epigenetic mechanisms such as DNA methylation, histone modification, and microRNA, all of which are part of the expression of genes and the DNA sequence.

The studies also found a correlation between an aged father and elevated incidences of schizophrenia, autism, and birth defects in children. Other factors such as dietary habits of the father, even in his pre-adolescence stage of life, were found to increase the chances of cardiovascular death in his children and grandchildren.

Moreover, the father’s obesity was observed to be linked with metabolic disorders, including diabetes, obesity and development of brain cancer. Psychological disturbances such as increased stress and paternal alcohol consumption were also seen to negatively impair behavioral traits of offspring. Due to small brain weight, a significant reduction in cognitive functions was also reported.

Another very important finding of the analytical review was the adverse effect of the father’s smoking habits, which irradiated and changed the male parent’s spermatozoa, eventually causing severe damage to the child’s DNA.

This research, carried out by Georgetown University Medical Center (GUMC), USA, is being considered revolutionary in the field of epigenetics, since previous studies were solely focused on congenital trends regarding the mother’s habits and lifestyle changes. The current study has provided interesting insights into observing the phenomenon from a different perspective.

Joanna Kitlinska, PhD, Associate Professor of Biochemistry, Molecular and Cellular Biology and the lead author of the review, stated that they already knew that the nutritional, hormonal and psychological environment provided by the mother has a direct effect in permanently altering the organ structure, cellular response and gene expression in her offspring. She added, “But our study shows the same thing to be true with fathers — his lifestyle, and how old he is, can be reflected in molecules that control gene function.” Similarly, she believes that a father can affect not only his immediate offspring but future generations as well.

Professor Kitlinska reiterated her point by giving an example of a newborn diagnosed with fetal alcohol spectrum disorder (FASD), despite the fact that the mother had never consumed alcohol, thereby linking the anomaly to the father. She affirmed that 75% of children diagnosed with FASD have biological fathers who happen to be alcoholics, with the statistics highlighting the negative impact caused to the offspring due to pre-conceptual ‘paternal’ alcohol consumption.

AJSC further emphasized upon the need for organizing this newfound field of inherited paternal epigenetics into clinically applicable recommendations and lifestyle alternations, to help prevent serious health complications, such as  birth defects. Moreover, Dr Kitlinska urged upon studying the interplay between maternal and paternal effects, which might lead to a combined effect responsible for altering genetic makeup of the child, rather than considering the effect from each parent individually. She believed that by focusing on the genetic effect from both parents, the epigenetic influences of a child can be understood in a better way.

Additional scientific evidence from a study revealed that the fathers who were above 25 years of age had increased risk of giving birth to a schizophrenic child, with the risk increasing in each 5-year age group. The highest risks were found among offspring of men aged 45 and older.

Another study published in Journal of the American Medical Association (JAMA) Psychiatry indicated that offspring born to men in their 40s were 5.75 times more likely to have autism compared to the children of younger men aged 30.

Moreover, the increased risks of birth defects including heart defects, tracheo-esophageal fistula, esophageal atresia, Down syndrome and other musculoskeletal and chromosomal abnormalities were also reported by a US-based cohort study published in the Oxford Journals.

The fetal alcohol spectrum disorder in children born to alcohol-treated fathers was also confirmed by another study which showed a higher prevalence of low birth weights among offspring. It should be noted that low birth weight’s relation to FASD is an established fact.

The co-authors of the study are graduates of Georgetown’s Special Masters Program in Physiology from Georgetown University, Washington, DC.