Answer:
The chances of the baby being a girl are 50%
Step-by-step explanation:
The chances of a baby being born a boy or girl are called, by the probability of a multi-exclusive event. We say that two events are mutually exclusive when the realization of one, excludes the realization of the other, so each event has a 50% chance of happening.
A baby's gender is a multi-exclusive event, since when one gender occurs (female, male) it excludes the other. Therefore, a baby has a 50% chance of being born a boy and a 50% chance of being born a girl.
This can also be seen using the Punnet Square. In that case, you would make a two-column, two-row table and place the hand's sex comosomes in the first row and the father's sex chromosomes in the first column, then just look at the combinations.
In this case, you will see that the results will be XX (girl, 25% chance), XX (girl, 25% chance), XY (boy, 25% chance), XY (boy, 25% chance). Conclusion: There is a 50% chance of a baby being born a girl and a 50% chance of being born a boy.