The vertebral cross-sectional dimensions, which is a key structural determinant of the vertebra's strength, was 10.6 % smaller on average in newborn females than in males.
![Boys Are Born With Stronger Spines Compared To Girls At Birth Boys Are Born With Stronger Spines Compared To Girls At Birth](https://images.medindia.net/health-images/1200_1000/spinal-cord-injury1.jpg)
"Human beings are the only mammals in which this difference is seen, and it is one of the few key physiological differences between the sexes," said senior study author Vicente Gilsanz from The Saban Research Institute of Children's Hospital Los Angeles, US.
Results of the study published online in the Journal of Pediatrics suggest that this difference is evolutionary, allowing the female spine to adapt to the fetal load during pregnancy.
But this difference in vertebrae makes women more vulnerable to scoliosis - an abnormal curving of the spine and the bone disease osteoporosis, the study said.
In the study, 70 healthy, full-term newborns (35 boys and 35 girls) were measured. Weight, body length, and head and waist circumference did not significantly differ between sexes.
Compared to newborn boys, girls had significantly smaller vertebral cross-sectional dimensions - a difference independent of gestational age, birth weight and body length.
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The study noted that, over their lifetimes, women also accumulate less bone mass than men, resulting in a two- to four-fold increase in spinal fracture.
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Source-IANS