It sounds like you are combining two different genetic test results. I hope the following information about MTHFR and Cystic Fibrosis is helpful.
Variants in the MTHFR (methylene-tetra-hydrofolate-reductase) gene are found in all populations with varying frequency, but are not uncommon. The MTHFR gene is important in the metabolism of the amino acid homocysteine. Variants in the gene are inherited. I am assuming from your message that you have one copy of the C677T mutation in the MTHFR gene. I recommend you request a copy of your report from your doctor to read for yourself and to keep a copy for your medical records. You can also provide a copy to your family if you want so they know what to look for. Once you have the report in hand, specific risks to carry the same mutation(s) for your family can be determined.
In some studies, The C677T variant has been associated with an increased risk of cardiovascular disease in adults and with problems in pregnancy. It is important to keep in mind, that there are many factors that influence the risk of these problems. Mutations in MTHFR can impact your homocysteine level in a negative way. Taking folic acid may help stabilize the homocysteine. Having "normal" levels of homocysteine is important for you health. I would suggest that you discuss testing your homocysteine levels as a next step with your healthcare provider
You may wish to consider visiting a genetic counselor as well to learn more about MTFHR, how it is inherited, and other health implications with your family. DNA Direct can offer these services online to you and your family, or a genetic counselor can be found through the National Society of Genetic Counselors.
Cystic Fibrosis (CF) is a separate genetic condition that is unrelated to MTHFR. CF is a chronic genetic condition that affects the lungs and the digestive system. Genetic testing is available for this condition, and couples who are planning a pregnancy are generally offered carrier testing for CF. If you are interested in learning more about this type of screening, a genetic counselor can help you. Best Wishes to you.