Patty Duke's Son, Sean Astin, Was a Good Sport About Uncovering His Father's Identity

With renewed interest in her career as well as her personal life, interest resurfaced in the unusual story about how her son, Sean Astin, learned the true identity of his biological father.

[...] his mother wasn't entirely sure; when Sean was born in 1971, Duke was the subject of tabloid fodder as she'd ended a relationship with 17-year-old Desi Arnaz Jr., and then spontaneously married Michael Tell - a man who was subletting her apartment - before divorcing him 13 days later.

People notes how Austin came to be unsure about his conception, and had a DNA test done around 2001.