Jane Kaczmarek -- Good Genes or Good Docs?

Jane Kaczmarek is one hot mama.

Here's a 37-year-old version of the "Malcolm in the Middle" mom at a movie screening back in 1993 (left) and 25 years later ... the mother of three looks better -- and blonder -- than ever at a play opening in Pasadena earlier this year (right).

She's raising the bar.

The question is ...