Both of mine are more attached to me more than to daddy. They go to him for early morning scratches but where ever I go they are not far behind. This is because I train them, feed them, water them, exercise them, etc. Daddy just usually gives them affection but they really know that I am the giver of all good things and that if they want them, they had better listen to me! Not that I am strict with them but everything is done with positive reinforcement!

I think in general though you may be refering to the fact that in a pack the more strong and dominant member is alpha. The dogs recognize that the male human is stronger than the female and is usually more dominant. They see that mom says something and maybe the kids listen but when dad speaks the kids always listen. It is basically just pack hierachy! If the male is assertive and strong then they will honor his place in the pack.