Mia Farrow's Son Dies at 27

Mia Farrow's son, Thaddeus Farrow, died Wednesday ... TMZ has learned.

Thaddeus died at Danbury Hospital in Connecticut, where Mia lives. Law enforcement confirmed he died from a life-threatening injury he suffered in his car ... and there was no foul play. There are no other details at this time. He was 27.

Mia adopted Thaddeus -- who was paraplegic due to polio -- in 1994 from Calcutta, India. He was one of 10 children Mia has adopted.

Thaddeus was adopted after Mia's split from Woody Allen.