Smoking babies?
It the cafe scene, at the end of the film. Karen Allen's character, 'Jenny Hayden' is smoking.
When Charles Martin Smith 'Mark Shermin' is in the foreground talking to the cop.
You can see Karen puffing away on a cigarette, it's smoke rising in the air.
If she had found out the night before... that she was 'miraculously' now pregnant,
with a future leader and teacher of mankind... would she really be smoking/would the 'Starman' even let her?
So it must be... that the scene on the train, ( alien-baby-daddy-scene ) was 'added in' much later on?