Hereditary diseases are diseases caused by gene mutations or chromosomal abnormalities that can be passed from parents to children. Pregnancy screening can usually be done before preparing for pregnancy.
1. Diabetes
Type 1 diabetes is an immune disease that occurs in children or adolescents, and its inheritance is relatively \”obvious.\”
Type 2 diabetes is a metabolic disease that occurs in adulthood and has complex genetics.
Genetic probability
It is difficult to calculate accurately, but the risk is higher if both parents have a family history. 
2. Down syndrome (trisomy 21 or trisomy 21)
It is caused by abnormalities in the number or structure of chromosomes. The heritability is not high, but it is closely related to the maternal age and whether there is a family history.
Genetic probability
Risk is positively correlated with maternal age.
3. Thalassemia (thalassemia or beta-thalassemia)
A common hereditary blood disease with relatively high heritability.
Genetic probability
If both parents are carriers, the child has a 25% chance of having thalassemia, a 50% chance of being an asymptomatic carrier, and a 25% chance of being completely healthy.
4. Hereditary Breast Cancer and Ovarian Cancer
Heritability is relatively high, especially when it comes to specific genetic mutations.
Genetic probability
If both parents have a medical history, the child has a 25% chance of not carrying any mutated genes, a 50% chance of being a carrier of one of the mutated genes, and a 25% chance of carrying two mutated genes at the same time (the risk is higher, but rare).
Only one parent is a carrier, and the child has a 50% chance of becoming a carrier of the mutated gene. Depending on the mutation and family history, the lifetime risk of developing breast cancer may be about 45% to 85%, and the risk of ovarian cancer is The risk is about 11%~65%.
5. Hereditary hypertension
Heritability is relatively high and it is a polygenic genetic disease.
Genetic probability
It is difficult to calculate precisely, but family history increases the risk. 
6. Hereditary heart disease
is aA broad term that includes a variety of heart diseases that are influenced by genetic factors.
Certain types of hereditary heart disease are highly heritable, such as Marfan syndrome, long QT syndrome, hypertrophic cardiomyopathy, and familial hypercholesterolemia.
Genetic probability
1. Autosomal dominant genetic disease
If one parent has a disease, the children have a 50% chance of inheriting the mutated gene and may develop the disease.
If both parents have the disease, the child has a 25% chance of not inheriting any mutated genes, a 50% chance of inheriting a mutated gene from one parent, and a 25% chance of inheriting a mutated gene from both parents.
2. Autosomal recessive genetic diseases
Children of both parents who are asymptomatic carriers have a 25% chance of having the disease, a 50% chance of being asymptomatic carriers, and a 25% chance of being completely healthy.
