#Sexratio

A new study in a leading science journal challenges the idea that a baby’s sex is purely by chance. Analyzing more than 146,000 pregnancies from over 58,000 women across six decades, researchers found that some families are more likely to have multiple children of the same sex. This finding invites Thai readers to reconsider long-held family narratives about gender balance.

The core message is striking: the odds of a child being a boy or a girl in a family resemble a weighted coin flip rather than a flawless one. Genetic factors and maternal age appear to tilt the balance. Traditionally, many believed each pregnancy had a perfect 50-50 chance, but the new evidence points to non-random tendencies. For Thai families, this prompts reflection on cultural stories about gender that have guided generations.

A groundbreaking new study published in Science Advances has upended the commonly held belief that the sex of a baby is purely a matter of chance, revealing that birth sex patterns within families may follow unique, weighted probabilities. This research—based on more than 146,000 pregnancies from over 58,000 women across nearly six decades—suggests that some families have a higher likelihood of producing multiple children of the same sex, offering fresh insight into age-old questions about why some parents end up with, for instance, “all girls” or “all boys” (Washington Post).