Bipolar disorder, like all mental illnesses, tends to run in families, but developing bipolar disorder is a combination of genetic, psychological and environmental factors. Heredity or genetics tends to be a slightly larger factor. If you have one parent with bipolar disorder there is a 15 - 30% increased risk, if both parents have bipolar disorder there is a 50-75% increased risk. You can see there is a large range in these statistics because it is just one factor and difficult to determine the direct effect. About 5.7 million people have bipolar disorder in the United States or about 2.6% of the population. To get the most accurate statistics for you, I recommend you seek genetic counseling. This type of counseling can give you a more exact risk of your children inheriting bipolar disorder. Even if both parents have no history of mental illness, there are risks. Don't let your own history deter you from having children. You are right to be concerned and to seek information. Being a parent requires a lot of faith and hard work. Prepare yourself the best you can and enjoy the journey.