Breakfast has always been said to be the most important meal of the day.
Skipping breakfast is linked to an unhealthy lifestyle
But researchers say it could be even more crucial than previously thought, with those who skip the meal more likely to have an unhealthy lifestyle.
Missing breakfast can be seen as a way of saving time in the morning, or of losing weight.
But the Finnish researchers say those who miss breakfast tend to smoke more, drink more alcohol and take less exercise than those who make time for the meal.
And those who missed the meal were likely to be fatter, possibly because they are more likely to have unhealthy snacks mid-morning to boost their energy levels.
They were also likely to be less well-educated, making it harder for them to get a job.
Researchers asked 5,500 teenagers and their parents if they ate breakfast, and if so, how often.
They were also asked about their education, weight and drinking habits.
It was found children of parents who skipped breakfast followed their example.
Dr Anna Keski-Rahkonen, who led the research at Helsinki University, told a national newspaper: "Children of breakfast-skipping parents were much more likely to skip it themselves.
"During early and mid-adolescence, disordered eating patterns are very strongly associated with health-compromising behaviours like use of tobacco, alcohol and marijuana."
She added: "Smoking, infrequent exercise, a low level of education, frequent alcohol use and a high body mass index were all associated with skipping breakfast in adults and adolescents.
"Our findings suggest that this association exists throughout adulthood.
"Individuals who skip breakfast may care less about their health than those who eat breakfast."
Amanda Wynne of the British Dietetic Association told BBC News Online the research was interesting.
But she said: "Just because people who skip breakfast also have these adverse health behaviours, it doesn't mean that one leads to the other.
"Breakfast is one of the most important meals of the day, because it replenishes your body's energy levels in the morning.
"Studies of schoolchildren have shown eating breakfast improves their concentration levels in the morning."
And she said people who were trying to lose weight were more successful if they had breakfast.
"People who skip breakfast tend to go on to have a snack mid-morning, usually something unhealthy like a chocolate bar."
The research is published in the European Journal of Clinical Investigation.