I dont think we really know. No one knows what genes are even involved in male pattern baldness or else we would have went in, and modified all those genes to cure it.
Your dad definitely has a strong influence on your male pattern baldness in many cases. Just from people I know, but you can get it from your moms side. It really can come from anywhere in your whole family tree, and get passed down generations but not get expressed until your the lucky one.