An idea I also had during the Cell saga was:
Always put your faith and power into the children as they are the future and are the ones you will be passing the tourch on to. Gohan had such a pure understanding of his heritage and history (mostly because he had a very good father figure who told him all the keys to life) that he eventually killed the evil of the universe due to pure emotion and understanding. Another message, not only is your past just as important as your present, but also, a father with knowledge of self can raise very powerful children.
The funny thing is, I heard another theory which is the complete opposite of this. My cousin is fatherless and so are alot of his best friends, and one of his friends brought it out in a convo one time .,... "you know goku is really a shyt father, he was never around unless it was fighting time, apart from that dude had to fend for himself"
this is another theory that could work ... most fatherless people I know are very strong people;