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 Researchers studied the timing of puberty for 672 girls and 846 boys
relative to their parents and found kids who developed pubic hair
and other hallmarks of adulthood at an unusually young age tended to
have mothers and fathers who also matured early.
“Both genetic and environmental factors undoubtedly influence
puberty timing,” said lead study author Dr. Christine Wohlfahrt-Veje,
a growth and development researcher at the University of Copenhagen.
“Our study shows that both boys and girls inherit from both mothers
and fathers, but indicates that the early pubertal markers – onset
of breasts and pubic hair – in girls are less dependent on genetic
and hence more on environmental factors such as childhood growth
patterns and possibly other environmental exposures,” Wohlfahrt-Veje
added by email.
Children who go through early puberty may be shorter than average
adults because after their early growth spurt their bones may stop
growing at a younger age, and they are also at increased risk of
obesity as adults. During adolescence, they may face an increased
risk of social and emotional problems and earlier sexual
experiences.
Some recent research points to earlier puberty onset in general,
especially in girls in developed countries. Environmental factors
like diet, obesity and chemicals that mimic human hormones have all
been suspected of playing a role.
To look at the contribution of genetics to puberty timing,
Wohlfahrt-Veje and colleagues examined medical records from annual
checkups kids received between 2006 and 2013 as well as data on
parental puberty timing from questionnaires completed by their
parents.
When fathers matured early, boys tended to develop pubic hair almost
one year ahead of boys with fathers who went through puberty late.
Sons of men who developed early also grew enlarged testes about 9.5
months sooner than sons of fathers who went through puberty late.
Girls with fathers that matured early started menstruating about
10.5 months sooner than girls with late-bloomers for fathers, and
the girls of fathers who went through early puberty also developed
pubic hair around 7 months before girls whose fathers developed
late. Early breast development in girls, however, didn’t appear to
be tied to early puberty in their fathers.
When mothers went through puberty early, their sons and daughters
tended to follow suit.
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Daughters of women who matured early typically started menstruating
about 10 months sooner than girls with late-blooming mothers.
Sons of women who went through puberty early typically went through
genital maturation about 6.5 months before boys with mothers who
developed late.
One shortcoming of the study is that researchers relied on parents
to accurately recall and report on when they went through puberty
many years earlier. They also got more data from mothers than
fathers, which may have affected the relative influence of each
parent in the results.
Because the study didn’t find as strong an association with parental
puberty timing and breast development in girls, this suggests that
other factors beyond genetics may influence puberty in girls, the
authors conclude in the Journal of Clinical Endocrinology and
Metabolism.
“A broad normal variation exists within timing of puberty,”
Wohlfahrt-Veje noted.
Still, when kids develop early, they quite likely came from a long
line of early bloomers.
“A large proportion of this variation seems to be explained by
genetics,” Wohlfahrt-Veje added. “If either the mother or father had
early or late pubertal development it is likely to influence the
timing of pubertal onset in both their sons and daughters.”
SOURCE: http://bit.ly/1Sd55zL Journal of Clinical Endocrinology and
Metabolism, online March 25, 2016.
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