BT August 2019

BT Buzz
Boy or girl? It’s in the father’s genes
A Newcastle University study involving thousands of families
is helping prospective parents work out whether they are
likely to have sons or daughters. The work by Corry Gellatly, a
research scientist at the university, has shown that men inherit
a tendency to have more sons or more daughters from their
parents. This means that a man with many brothers is more
likely to have sons, while a man with many sisters is more
likely to have daughters.
The research involved a study of 927 family trees containing
information on 556,387 people from North America and
Europe going back to 1600. “The family tree study showed
that whether you’re likely to have a boy or a girl is inherited.
We now know that men are more likely to have sons if they
have more brothers but are more likely to have daughters if
they have more sisters. However, in women, you just can’t
predict it,” Mr Gellatly explains.
Low vitamin D at birth raises risk
of higher blood pressure in kids
Vitamin D deficiency from birth to early childhood was
associated with an increased risk of elevated blood pressure in
later childhood and adolescence, according to new research in
the American Heart Association journal Hypertension.
Researchers followed 775 children from birth to age
18 at the Boston Medical Center. Most lived in a lowincome,
urban area and 68% of the children were African
American. Low vitamin D levels were defined as less
than 11 ng/ml (nanograms per millimeter) in cord blood
at birth and less than 25 ng/ml in a child’s blood during
early childhood. Compared to children who were born
with adequate vitamin D levels, those born with low levels
of vitamin D had an approximately 60% higher risk of
elevated systolic blood pressure between ages 6 and 18.
Both mother and baby genes affect
birth weight
The largest study of its kind has led to new insights into the
complex relationships surrounding how mothers’ and babies’
genes influence birth weight. The research, published in
Nature Genetics, identifies 190 links between our genetic
code and birth weight, two-thirds of which are identified
for the first time. It is the result of a large scale international
collaboration, led by the universities of Exeter, Queensland,
Oxford and Cambridge.
Scientists have long known that babies who are particularly
small at birth have a higher risk of birth complications, and also
tend to be more prone than average weight babies to high
blood pressure in adulthood. To understand the relationships
between birth weight and such risks to health, it is necessary to understand the contributions of both genetics and the
environment. But until now, these have been unclear. This study casts new light in this area by allowing scientists to clearly
separate the effects of a mother’s genetics on birth weight from the baby’s own genetics for the first time.
8 BabyTalk | August 2019