Maybe you find this at your house. When my 9-and 13-year-old sons come home from school ready to unwind or get up on Saturday looking for a challenge, they immerse themselves in a video fantasy world.

Using cartridges, an open channel on the TV set and a control pad, they manipulate buttons furiously with their thumbs. Their eyes become more and more narrow and focused as they play the game with the catchy electronic sound track. Once again they are hooked on Nintendo.There are apparently millions of American boys who do the same. Many of them are addicted to home video games made by a Japanese company called Nintendo. Nintendo games are considered more complex and vivid than the video game pioneers, such as "Pac-Man" and "Space Invaders," now obviously outdated.

The favorite at our house, only recently acquired, is "Super Mario Bros.," which just happens to be one of the most popular video games in the world. Mario and his brother, Luigi, are maneuvered in a complicated search for the captive princess Toadstool.

Mario and Luigi are only about 2 inches tall on the TV screen, and have mustaches and oversized noses. They shoot, squash or evade their enemies with a certain charm not apparent in other video games.

Some skeptics are predicting that Nintendo's sales and popularity will wane in late 1989 or early 1990, following the fate of all video games. But Nintendo has a library of more than 100 games and is always adding titles. At 60 hours to master each game, Nintendo could go on forever.

While Nintendo seems harmless enough as we watch our kids playing it, there should be some second thoughts. A lot of aggression is played out in video games. Some psychologists have claimed that purging such aggression is healthy, but others believe that participation in the games only creates more hyperactivity. Those who are absorbed in the role playing of the games may carry over the feelings into real life.

Just as worrisome is the fear that Nintendo immerses players in a fantasy world where violence is the means of settling disputes and women play only passive roles.

A California study in 1984 by Sarah Rushbrook, a psychologist, reviewed almost 1,000 video games and found that 70 percent had violent themes. Two percent of the games contained active women and 98 percent had either no women or passive ones.

Since Nintendo's "Super Mario Bros." depicts active men saving helpless women, the image created in boys' minds is a disturbing stereotype. Girls, who otherwise might play the games as one way to introduce themselves to computers, are alienated.

It boils down to the fact that too much time spent in video games may not only produce a tendency to violence in those who play, but perpetuate a sexism that may have a solid influence on personal relationships.

The Nintendo explosion has produced something else of interest, especially to those who have become video game experts. Young people, almost exclusively young men, can obtain employment as game counselors. Young men in their 20s work in cubicles containing a desk, a phone, a television and a Nintendo system. They take calls from all over the world from video junkies who need help with a game.

These counselors get calls from boys at every imaginable time - suggesting that at least some of the millions of boys hooked on Nintendo are playing when they probably ought to be studying, sleeping or reading.

Although this phenomenon is but another example of the continuing dominance of the Japanese in American business, the greater concern is how much control is exercised by the system over the minds of young boys. It would seem especially important that all of us who participate in the addiction become aware of the need to achieve a balance with a myriad of life's other pursuits. Young men cannot live by Nintendo alone.