Finally an explanation : Genetics !

The title of the post is one of my friends comment, upon hearing the below incident.
A few days ago..
Sheela ki jawani songs on tv. Amma watches very few hindi stuff, that too only when we compel her and hold her eyes open.[ How she manages to doze off within 10 mins, that too with our high pitched non stop gibberish around is something i never understand.] However this is one song she likes. After watching for a minute her as usual unanswerable doubts pop up.
Amma : Which is this heroine ? Kareena ?
Me : Katrina.
Amma : Her character in the movies mentally unstable or something ???
Me: I havent seen the movie. But I really dont think so.
Amma : Does she have that disease amir khan had in Gajni ??
Me [raising eyebrow]: Short term memory loss ? No. Where in world did you get that idea from???
Amma : Then why is she going around asking everyone 'Whats my name?' !!!