Gentlemen, whereas I am typically harder on women on this subject, you are as much to blame.
If you or someone you know think that you may have fathered a child, please, please seek to have a paternity test to determine the results. If you are, you have a responsibility to that child to be a parent and help in the growth and development of the child.
Children deserve to have their fathers in their lives. If for some reason you feel inadequate as a father, seek help and guidance from friends and family. I'm sure that family members would appreciate your desire to be a father and help in whatever ways they can.
No one is perfect. Not mothers, not fathers.
Children grow up and become the adults that they are in large part of their upbringing. Be a part of that and always, always encourage them to be good citizens, even if you are not. Be honest with them as to not seem hypocritical. Admit mistakes and advise why they might not make those same mistakes.
Children can discern deception. Keep it as real as you can.
Most of all, gentlemen, be there, show love and encouragement to you children.