According to WebMD, blood type may influence health risks.
**Stomach Cancer & Ulcers**
People with type A blood face a higher risk of stomach cancer, possibly due to a greater likelihood of *H. pylori* infection. “It can cause inflammation and ulcers.” Meanwhile, type O individuals are more prone to peptic ulcers, painful sores in the stomach lining.

**Blood Clots & Stroke**
Venous thromboembolism (VTE), a serious blood clotting condition, is more common in types A, B, and AB. Additionally, “your risk for a stroke goes up if you have blood type AB.” This may be due to increased clotting tendencies.

**Diabetes & Heart Disease**
Type 2 diabetes appears more frequently in people with blood types A and B, though the reason is unclear. On the other hand, “there’s good news for O blood types”—they have a lower risk of coronary heart disease, possibly due to lower cholesterol and clot-related proteins.

**Fertility & Memory**
Blood type may play a role in fertility, as women with fewer healthy eggs were more often type O. Memory issues also seemed more frequent in people with type AB blood.

**Stress & Malaria**
Type A individuals tend to have higher cortisol levels, making stress harder to manage. Meanwhile, type O blood might offer some protection against malaria, as the parasite struggles to attach to these cells.