All through our lives we have chosen favorites, from marbles to teachers, from sport figures to sport cars, from houses to political parties, from schools to churches. We all have favorites and are usually ready to state why.
We can have a favorite aunt or uncle, a favorite niece or nephew but it stops there. To have a favorite great-grandson, grandson or son is a no-no. Partiality should not be shown in reference to offsprings.
Come on. They are all individuals and some are more capable of excelling than others. Love them equally but to say you don't have favorites? You are just fooling yourself.