From a group of 3 boys and 3 girls, 4 children are to be randomly selected.  What is the probability that equal numbers of boys and girls will be selected?

~\frac{1}{10}~

~$\frac{4}{9}$~

~$\frac{1}{2}$~

~$\frac{3}{5}$~

~$\frac{2}{3}$~