The famously private Robert Redford has never fully recovered from the tragic SIDS death of his baby boy more than 50 years ago, he says in a rare interview.

Redford's son with first wife Lola Van Wagenen died of sudden infant death syndrome when he was only 5 months old, in 1959.

"It was really hard," Redford, 74, tells AARP The Magazine for its March/April cover story. "We were very young. I had my first theater job, which didn't pay much. We didn't know anything about SIDS, so the only thing you think is that you've done something wrong. As a parent, you tend to blame yourself. That creates a scar that probably never completely heals."

Redford and Van Wagenen, whom he divorced in 1985 after almost 30 years of marriage, had three other children together. The actor, director and founder of the Sundance Film Festival remained single until 2009, when he married longtime girlfriend Sibylle Szaggars.