Planning a Family? Your Genes May Determine Your Children's Health.

BRCA1 is a tumor suppressor gene that normally acts as your cells’ primary DNA repair system. When DNA breaks occur (from radiation, aging, or simple cellular division), BRCA1 steps in to fix the damage before it becomes permanent. This job is critical. Without functional BRCA1, mutations accumulate, and cells begin the transformation into cancer.

Pathogenic BRCA1 mutations are carried by roughly 1 in 400 people in the general population, though rates are higher in people of Ashkenazi Jewish descent. When you carry a pathogenic BRCA1 variant, your cells lose this repair function. The result is a 55-72% lifetime risk of developing breast cancer, and elevated risks for ovarian, pancreatic, and prostate cancers as well. This is not a 5% increase in risk. This is majority-probability: most people with pathogenic BRCA1 mutations will develop cancer in their lifetime.

For your children, the implications are profound. If you carry a BRCA1 mutation, each of your children has a 50% chance of inheriting it. That means your daughter could inherit your genetic vulnerability to breast cancer. Your son could inherit increased prostate cancer risk. Understanding your BRCA1 status before conception allows you to make informed choices about genetic counseling, prenatal testing, and family planning.

BRCA2 is another critical DNA repair gene, working as a partner and localizer for BRCA1. When BRCA1 detects DNA damage, BRCA2 helps position the repair machinery correctly. Together, they’re your cells’ first line of defense against the mutations that become cancer.

Roughly 1 in 800 people in the general population carry a pathogenic BRCA2 mutation. Like BRCA1, when this gene is impaired, DNA damage accumulates. The lifetime breast cancer risk with a pathogenic BRCA2 mutation is 45-69%, and there’s also elevated risk for ovarian cancer, pancreatic cancer, and male breast cancer. For men, BRCA2 mutations carry particular weight: male breast cancer risk rises significantly, and prostate cancer risk is also elevated.

If you’re planning to have children, knowing your BRCA2 status changes everything. Your children who inherit the mutation face the same cancer risks you do, starting in their teens or twenties. This is not information that emerges in your 40s when cancer appears. This is knowledge that shapes medical decisions, screening protocols, and family conversations from adolescence onward.

Factor V is a protein that sits at the center of your blood’s clotting cascade. When you bleed, Factor V is activated and helps recruit platelets and other clotting factors to seal the wound. Once the bleeding stops, a protein called activated protein C degrades Factor V to prevent excessive clotting. This balance between clotting and anti-clotting is critical.

The Factor V Leiden variant (R506Q) is carried by roughly 5% of people with European ancestry. In people with this variant, Factor V cannot be degraded by activated protein C. The result is hypercoagulability: blood clots more readily, increasing venous thromboembolism risk 4-8 fold compared to people without the variant. But here’s the critical detail for family planning: the risk skyrockets in the presence of oral contraceptives or pregnancy. Pregnancy naturally increases clotting risk. Adding Factor V Leiden to pregnancy can increase thromboembolism risk by 5-10 fold or more. Oral contraceptives amplify the risk even further: women with Factor V Leiden who use oral contraceptives face up to 80 times greater risk of deep vein thrombosis or pulmonary embolism compared to women without the variant.

For your children, Factor V Leiden is inherited with 50% probability per child. But the immediate implications are for you and your pregnancy. If you carry Factor V Leiden, pregnancy requires careful management: anticoagulation therapy, leg elevation, compression stockings, and close monitoring. This is not a minor consideration. This is a medical reality that changes how your pregnancy is managed, and your future children’s health trajectories.

MTHFR catalyzes one of the most important reactions in your body: converting dietary folate into methylfolate, the active form your cells actually use. This methylfolate fuels the methylation cycle, which affects DNA synthesis, neurotransmitter production, detoxification, and energy metabolism. Almost every cell process depends on this gene working correctly.

The MTHFR C677T variant is incredibly common, carried by roughly 40% of people with European ancestry. This variant reduces MTHFR enzyme activity by 40-70%. The consequence is impaired folate metabolism: even if you eat plenty of folate-rich foods, your cells struggle to convert dietary folate into the active form they need. This creates functional folate deficiency at the cellular level, despite normal serum folate levels on bloodwork.

For pregnancy planning, MTHFR variants are particularly important. Adequate folate is essential for fetal neural tube development. Impaired folate metabolism increases miscarriage risk and birth defect risk, particularly neural tube defects. For your children, if they inherit your MTHFR variants, they start life with the same folate metabolism challenges. This affects neurodevelopment, energy production, immune function, and cardiovascular health throughout their lives. Understanding your MTHFR status before conception allows you to optimize folate intake and form before pregnancy, reducing risk for you and your children.

HBB encodes the beta-globin subunit of hemoglobin, the protein in red blood cells that carries oxygen. Normal hemoglobin molecules are flexible and can navigate through tiny capillaries easily. The hemoglobin molecules stay dissolved in the cell and don’t cause problems.

Sickle cell variants in HBB cause hemoglobin to polymerize (link together) when oxygen levels drop, distorting red blood cells into sickle or crescent shapes. Pathogenic HBB variants vary widely in prevalence depending on ancestry, but are most common in people of African, Mediterranean, and Middle Eastern descent. In people with one HBB variant (heterozygous carriers, or sickle cell trait), symptoms are typically mild, but severe anemia, pain crises, and organ damage occur in people with two copies (homozygous, or sickle cell disease). If both parents carry sickle cell trait, each child has a 25% chance of being born with sickle cell disease.

For family planning, understanding your HBB status is crucial if you carry variants. If you and your partner both carry sickle cell trait, genetic counseling and prenatal testing become essential conversations. Your children who inherit two copies face a life with unpredictable pain crises, organ complications, and shortened lifespan. Children with one copy (trait) typically live normal lives but should be aware of their carrier status before having their own children.

HLA-DQ2 is part of your immune system’s antigen presentation machinery. When your immune system encounters a foreign protein (from food, bacteria, or viruses), HLA molecules display fragments of that protein to T cells, which decide whether to mount an immune response. HLA-DQ2 is one of the most common HLA variants, present in roughly 30-40% of the general population depending on ancestry.

HLA-DQ2 becomes problematic when it encounters gluten, the protein in wheat, barley, and rye. In people with HLA-DQ2, the immune system recognizes gluten as a threat and attacks the small intestine. The result is celiac disease: chronic intestinal inflammation, nutrient malabsorption, and systemic autoimmune effects affecting bones, brain, thyroid, and reproductive health. Celiac disease affects roughly 1-3% of people with HLA-DQ2, meaning the gene is necessary but not sufficient for disease development. Environmental triggers (infection, stress, pregnancy) can activate celiac disease in genetically susceptible people at any age.

For your children, if you carry HLA-DQ2, they have a 50% chance of inheriting it. If they inherit the gene and are exposed to gluten, they may develop celiac disease. More importantly, if you have celiac disease, understanding this before pregnancy is critical. Untreated celiac disease impairs nutrient absorption, increasing miscarriage risk and birth defect risk. Managing celiac disease (strict gluten avoidance) before and during pregnancy improves outcomes for both you and your children.