The Generation 1 games are heavily influenced by Satoshi Tajiri's childhood. During that time period, as well as for the most part nowadays, the father of the modern Japanese family is seldom at home. Men in Japan either live close to, or spend most of their time at their jobs, while the women raise the children and live at home. It is regarded that an absent father is a sign of a successful business man. More than likely the player's parent does not live at home or spends most of their time away, leaving only a mother to have the most influence at home.
Some even work themselves to death, which could also be the case. There is an entire movement dedicated to Japanese families that have lost their husbands/fathers to something called Karōshi, meaning "Death from Overwork". It is unfortunately common.