a good son

प्रदोषे दीपकः चन्द्रः प्रभाते दीपको रविः।

त्रैलोक्ये दीपको धर्मः सुपुत्रः कुलदीपकः॥

pradoṣe dīpakaḥ candraḥ prabhāte dīpako raviḥ|

trailokye dīpako dharmaḥ suputraḥ kuladīpakaḥ||

When the evening arrives the moon also appears in the sky to give us light

Our mornings are brightened by the sun

The dharmas, the eternal laws of virtue are there to provide the light of knowledge and welfare for all the three worlds..

And a son, born and brought up well becomes the one who keeps aloft the light for the clan and the family .

Note..There is a convention in Sanskrit literature that universally applicable truths are presented in the masculine gender..

We find that convention even in law and legislation too

So a daughter born and brought up well will also prove to be an equally great boon for the family and the clan.. 

Sita was the pride of Janaka, no doubt..

The sun, moon or even the eternal law are beyond our control..

But sure, we can shape the character and behaviour of a child.. be it boy or girl..

चन्द्रः प्रदोषे दीपकः भवति the moon becomes the provider of light in the dusk 

प्रभाते रविः दीपकः भवति the sun provides light in the mornigs. त्रैलोक्ये धर्मः दीपकः भवति the path of virtue and the eternal laws enlighten all the three worlds. 

सुपुत्रः कुलदीपकः भवति a good son becomes the light of the clan and the race..