Steven Forrest says, "A person with Pluto in the 4th was born remembering something most of us forget: clan, hearth, family. Bonded, unbreakable relationships"
The whole chart has to be considered as mentioned by others. One possibility with the Mars in the 10th opposing Pluto in the 4th is he maybe very career driven and responsibilities of his commitment and dedication to family oppose his drive to achieve in the public world.
I remember when I had my first baby and being worried about his Moon trine Pluto...all the bad talk of Moon-Pluto aspects against mothers. I attended a workshop with Noel Tyl and he said "don't worry about the trines my dear!" We want our children to be problem free, but that is not a reality. Their little souls came here with instructions (the astrology chart) and as parents we're players in that plan. We love them and do the best that we can, that includes the best potential in the astrology chart too. There are so many ways these aspects can play out, oppositions are about balancing, squares I think create strength. I don't see any of it as purely negative.
A poem by Kahil Gibran that I had to hang in my boys' bedroom to remind me:
Your children are not your children.
They are the sons and daughters of Life's longing for itself.
They come through you but not from you,
And though they are with you yet they belong not to you.
You may give them your love but not your thoughts,
For they have their own thoughts.
You may house their bodies but not their souls,
For their souls dwell in the house of tomorrow,
which you cannot visit, not even in your dreams.
You may strive to be like them,
but seek not to make them like you.
For life goes not backward nor tarries with yesterday.
Letting go and allowing them to follow their path is a very hard thing to do, but do it we must so they can thrive and build confidence and fulfill their purpose. My main point is focus on the positive things you have control of and do your best and remember children have their own path to follow.
I just sent my first born off to Iraq for a year, hardest thing yet, but I have to let go and let him use his wings.