Consultant paediatrician Victor Grech. Photo: Matthew Mirabelli

The stress leading up to the hotly contested parliamentary elections in Malta causes the proportion of male babies born to decline, according to the first study of its kind.

In a study published in an international journal, consultant paediatrician Victor Grech examined the relationship between parliamentary elections in Malta and the male-to-female ratio of births.

Elections in Malta are held in a highly stressful and divisive political climate, with voter turnout approaching 100 per cent, Prof. Grech noted.

Since the early 1970s, the country has developed one of the most unalloyed two-party systems in existence, a structure that has produced intense political polarisation of most of Maltese society.

This fact has been well documented by various researchers.

“Politics has been mooted as the principal cause of division within Maltese society, and elections further expose political divisions and disagreements that might normally be concealed or ignored. This may potentially stress the population.”

Stress is a factor known to reduce the male-to-female birth ratio.

Usually, the sex ratio (the number of boys born divided by the number of girls born) is slightly greater than one. In fact, worldwide, about 106 boys are born for every 100 girls.

The male-to-female ratio at birth has been shown to be influenced by a plethora of factors, Prof. Grech continued.

Stressors (such as unemployment and workplace factors) and toxins tend to reduce the ratio since, under such circumstances, pregnant women tend to spontaneously miscarry, losing male pregnancies at a greater rate than female pregnancies.

There was a decline in the sex ratio from seven months prior to the election month

This is in accordance with the Trivers-Willard hypothesis, which proposes that female mammals have gained the ability, through evolution, to influence the sex ratio so as to favour the propagation of their genes under conditions of stress.

Prof. Grech examined monthly male and female births in the periods leading up to and following elections. He focused on 11 parliamentary elections held between 1966 and 2013.

There were 121,010 live births (62,783 males and 58,227 females) related to election years.

The mean male-to-female ratio was 0.51, ranging from 13 months before the election to 13 months after it.

Prof. Grech observed a decline in the sex ratio from seven months prior to the election month.

The mean male to female ratio for inter-election years stood at 0.52.

The study shows that parliamentary elections in Malta influence the male-to-female ratio, such that the number of male babies born in relation to the number of females born declines.

The effect appears to peak well before the actual election, falling rapidly afterwards.

The hypothesis that stress lowers this ratio is supported by studies that followed up the effects of stressful events on populations. For example, the ratio fell in New York City three months after the terrorist attacks of September 11, 2001.

These findings are further supported by a simultaneous increase in premature births, which rapidly recovered.

Similar findings were noted for the same time period following the above-mentioned terrorist attack in California, suggesting that witnessing harm befalling others induces biological responses that resemble those experienced by the people harmed.