Having only boys or girls may run in the family

It's not just chance: women who've had multiple children of the same sex are more likely to have another baby of the same sex

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Rather than every child having a truly random 50/50 chance of being a boy or a girl, maternal age and genetics could be 'weighting the coin toss' during conception, a new study has found.

Specifically, older mothers are more likely to have multiple children of the same sex, and two genes could increase the likelihood of having all-female or all-male children.