Newborn baby girls have better outcomes than boys due to a genetic advantage, new Irish research has revealed.

According to the findings, newborn girls have an innate advantage in responding to acute infections.

It is already known that females have a survival advantage throughout the entire human lifecycle, however according to this latest research, this is especially evident during the newborn phase.

Overall, newborn boys have higher rates of infection and sepsis (blood poisoning) than newborn girls of the same gestational age. Boys also have poorer survival.

The researchers said that the reason for this is down to chromosomes. In particular, females carry two copies of the X chromosome (XX), while males carry one X and one Y chromosome (XY).

The X chromosome contains more of the genes associated with immunity than the Y chromosome. As a result, girls have a higher expression of these immune genes than boys, providing them with an advantage when it comes to fighting off acute infections.

This may also have a role to play when it comes to gender differences that are seen in some diseases.

The researchers focused on the presence of a factor called interleukin-1 receptor-associated kinase 1 (IRAK1), which has a role to play in immunity against infection.

They measured the presence of IRAK1 in the umbilical cord of newborns and found higher levels in girls.

"The phenomenon of female neonates being hardier than their male counterparts is well recognised. This research shows this is due to a fundamental genetic advantage, which may also contribute to more effective responses to infection and disease throughout the human lifecycle," explained Prof Catherine Greene of the Royal College of Surgeons in Ireland (RCSI).

Meanwhile, according to the study's first author, David O'Driscoll of the RCSI, these findings in full-term babies ‘suggest that a similar phenomenon could be occurring in preterm infants where gender differences can be even more marked'.

This research involved a collaboration between RCSI researchers and neonatologist, Prof Eleanor Molloy, of Trinity College Dublin, who also works with a number of hospitals including the National Maternity Hospital.

Details of the findings are published in the journal, Pediatric Research.

*Pictured is Prof Catherine Greene, associate professor of clinical microbiology at the RCSI