When do we become 'our parents' ??

When is it....
 precisely...
that we happen to look into a  mirror
 (NOT the mirror at HOME!)
(an 'unfamiliar' mirror)
(usually one that we happen by on an escalator or in a store, etc...)
a GLIMPSE !
a MOVING IMAGE....
and for just a second,
a bat of an eyelash even,
we see one or BOTH OF OUR PARENTS looking back at us ?
Is this cumulative ?
Did it happen over time...
The presentation of genetic coding, and so forth ??
OR...
Does it just OCCUR one day ?
Randomly ?
Well...I guess not RANDOMLY,
(as we're referring to a pretty SPECIFIC phenomenon!)
In any case...
we've ALL been there...
in this moment....
in this WATERSHED moment....
when it is painfully clear that we are NOT KIDS any longer...
AU CONTRAIRE...
We've actually crossed over into the SECOND HALF of our life....
and so it goes....