Another issue that concerned gay rights advocates involved the automatic changing of data during the tabulation process. This automatic software data compiling method, called "allocation", was designed to counteract mistakes and discrepancies in returned questionnaires. Forms that were filled out by two same-sex persons who checked the "Husband/wife" relationship box were treated as a discrepancy. The Census Bureau explained that same-sex "Husband/wife" data samples were changed to "unmarried partner" by computer processing methods in 99% of the cases. In the remaining 1%, computer systems used one of two possibilities: a) one of the two listed sexes was changed, making the partnership appear heterosexual, or b) if the two partners were more than 15 years apart in age, they might have been reassigned into a familial parent/child relationship. The process of automatic reassignment of same-sex marriage data was initiated so that the Census Bureau would not contravene the Defense of Marriage Act passed in 1996. The Act states: