\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
Parents have three children, each either a boy (B) or a girl (G). The tree diagram below illustrates all 8 possible gender outcomes for the three children.
Calculate the probability that the family has at least two girls, simplifying the fraction.
\(P(\text{"at least two girls"}) =\)