What is the probability that the male progeny will be a boy?

According to the Mendelian theory, the F2 generation of the cross between a male  and female (XY and XX respectively) will produce offspring with genotype as XX(girl), XY(boy), XX(girl), and XY(boy). So, the probability that the progeny will be a boy (XY) is 2 out of 4 viz. 50% in a population.