50% because using the purett square you get exactly 50%.
You would imagine it to be about 50% but actually there are more baby boys born every year in the US than baby girls. The NCHS says that this...
1. The Chances of having a baby boy and a baby girl is 50/50 because the girls have XX Chromosomes and Boys have XY Chromosomes it's a 50% chance that it sprays some liquid to get the Y Chromosomes...