Your genes play an enormous role in what makes you, well, you. Since you inherit your genes from your parents, you tend to share things like hair type or athletic ability.

Unfortunately, we can also inherit 'changes' in genes from either our mother or father, which can increase the chances of developing an inherited disease, such as cancer.

Many families have a disease or condition that seems to "run in the family." But when should you actually worry about it?

It is recommended following these steps if you think you or your loved ones are at risk for developing an inherited disease.

The first step in understanding your risk is to learn about your family's health history. This means collecting information about relatives, including your parents, sisters, brothers, grandparents, aunts, uncles and cousins.

It's a good idea to ask about your family members' major medical conditions, including breast cancer (male and female), colon cancer, ovarian cancer, pancreatic cancer, prostate cancer, stomach cancer, as well as heart conditions like arrhythmias, hypercholesterolemia, enlarged heart, etc.

Gather information about relatives:

• Age at diagnosis of a major medical condition
• Ethnic background, for example Ashkenazi Jewish ancestry
• Cause of death, as well as age at death
• Having three or more close relatives with the same medical condition means you could be more likely to develop that condition yourself.

The pattern of inheritance of some diseases is pretty straightforward, but for others it's more complicated.

Sometimes all it takes to develop a disease is inheriting a gene change from just one parent. This is called an autosomal dominant single-gene disorder and includes:

• Huntington disease
• Marfan syndrome
• Neurofibromatosis type 1

If you have one of the diseases above, there's a 50% chance it will be passed on to each of your children.

Other times, both parents have to contribute a change in the same gene in order for a child to develop the genetic condition. This is called an autosomal recessive single-gene disorder and includes:

• Congenital deafness
• Cystic fibrosis
• Beta thalassemia
• Spinal muscular atrophy (SMA)
• Sickle-cell anemia
• Tay-sachs disease

A recessive single-gene disorder is often passed on by parents who don't know they carry the disease. If both parents are a carrier of a disease, each of their children has a 25% chance of inheriting the disease and a 50% chance of becoming a carrier himself or herself. These diseases usually aren't seen in each generation.

It is believed that all people probably carry about 5 or more genes associated with a recessive disorder that they may not know about.

Therefore, genetic testing or screening is offered to individuals who would like to know if they are carriers of recessive disorders — such as those who plan to get pregnant or have a family history of inherited disease.