However. I think it was unnecessary to limit the admission of unmarried sons and daughters to those who are under 21 years of age. According to the committees report. The elimination of unmarried sons and daughters over 21 reflects the committees view that the limited visas available for this preference should be used to reunite "nuclear families." Mr. President. I do not know of any legal definition of what a "nuclear family" is. but commonsense and past practice tells us that simply because a son or daughter reaches 21 he does not leave the nuclear familyespecially if he is unmarried.