"Full-time members of the staff, with the exception of those specifically excluded by resolution of the General Assernbly, shall be entitled to a children's allowance of $US200 per annum in respect of each child under the age of eighteen years, or, if the child is in full-time attendance at a school or a university ( or similar educational institution) or is totally disabled, under the age of twenty-one years; provided that, if both parents are rnembers of the staff of the United Nations, only one allowance will be paid in respect of each of their children ; and provided