Provide a short answer:
What is the probability of a girl or a boy being born in a family? Justify your answer.
Answer variants:
XX
mother
50%
75%
dad
XY
The probability of a girl or a boy being born in a family is approximately each (or 1/2), assuming no external factors influence gender determination. This is because human sex determination follows the random combination of chromosomes during reproduction. The contributes either an X or a Y chromosome, making the likelihood of a boy or girl nearly equal.