A Florida couple created a trust to benefit their grandchildren. The trust stated that it was to benefit only grandchildren who were related by blood. One of the couple’s sons got divorced in 1971. A girl, Catherine, had been born during the marriage. The son acknowledged the girl as his child and paid child support for her.

In 1999, however, when Catherine was 32 years old, a DNA test proved that she wasn’t really the son’s daughter.

In response, the other grandchildren went to court and argued that she shouldn’t be able to collect from the trust, since she wasn’t related by blood.

However, a Florida appeals court sided with Catherine. It said that while she might not be physically related by blood, she was legally related by blood. That’s because there’s a long legal history in Florida (going back many years before DNA tests) that considers any child born during wedlock as a blood relative.

The court also noted that the grandparents apparently never knew about the DNA test and always considered Catherine to be their grandchild.

If you’re concerned about potential illegitimate heirs or adopted heirs, there are other ways to draft trusts that can help carry out your wishes.