Hi everyone. I've tried the ways you all suggested. However, in order to keep the 1st childid if a woman had twins or all of her childdob missing ie id=4 and 5, I added a datastep with "if first.id". I wonder if this's nessary or such condition can be taken into account without having to write any extra datastep or SAS procedure. Thanks again in advance!! From A id childid dob 1 1 07/08/1980 1 2 04/04/1985 1 3 12/12/1987 2 4 . 2 5 01/02/1990 3 6 . 3 7 . 3 8 25/12/1995 4 9 . 4 10 . 5 11 08/08/1998 5 12 08/08/1998 to B id childid dob 1 1 07/08/1980 2 5 01/02/1990 3 8 25/12/1995 4 9 . 5 11 08/08/1998
... View more