The question "What side is a boy on?" is ambiguous and requires clarification. It likely refers to the old wives' tale regarding placental positioning and fetal sex.
Placental Position and Gender: An Old Wives' Tale
An unsubstantiated theory suggests that a boy's placenta is more likely to form on the right side of the uterus, while a girl's placenta is more likely to form on the left. This claim is not supported by scientific evidence. Mainstream medical experts dismiss this idea. [Source: (Reference provided: "If your placenta is forming on the right side of your uterus, the baby is most likely a boy, the theory claims. If it's forming on the left side, it's probably a girl. There's no evidence that it works, and mainstream experts dismiss it.")] Some people may choose to use this as a fun prediction, but it shouldn't be relied upon for determining the sex of a baby.
While the idea of determining the sex of the baby based on placental position is popular, it is crucial to understand it's just a myth. The actual sex of a baby is determined by the chromosomes (XX for female and XY for male) at conception.
