The Outer Limits - Season 3 Episode 3 Re-Generation

After their four-year-old son Justin dies in a household accident aspiring politician Graham Highfield and his wife Rebecca get a second chance at happiness. Dr. Lucy Cole clones a new embryo from Justin's brain and nerve cells and implants it in Rebecca's womb. As the pregnancy progresses, however, it becomes clear to Rebecca that this isn't just any fetus -- this is Justin himself, a fetus with the skills -- and the memories -- of a little boy. As he shares those memories with his mother, Justin reveals secrets that may destroy the whole family.