Fitness basics
Learning Center
Repeat C-sections: Is there a limit?
Repeat C-sections are common — but each C-section is generally more complicated than the last.
Secondary infertility: Why does it happen?
Second pregnancies don't always come easily. Learn about possible causes for secondary infertility and when to seek professional help.
Semen allergy: A cause of infertility?
Semen allergy, also called seminal plasma hypersensitivity, is a rare condition that can be easily misdiagnosed. Learn about symptoms and possible treatments.
Silicone breast implants: What happens if they rupture?
Understand the problems that may happen when a silicone breast implant leaks.
Sinus infection and toothache: Any connection?
Sometimes the cause of a toothache isn't a tooth problem, but a sinus problem.
Sleep deprivation: A cause of high blood pressure?
Too little sleep affects not only energy levels but also heart health.
Sperm: How long do they live after ejaculation?
After ejaculation, the life span of sperm depends on the circumstances.
Stool color: When to worry
Stool color is usually a result of diet and is only rarely a concern.
Sulfa allergy: Which medications should I avoid?
Sulfa allergy: A Mayo Clinic expert discusses which medications are likely to cause problems.
Testicular microlithiasis: Is it linked with testicular cancer?
A Mayo Clinic specialist discusses the relationship between testicular microlithiasis and testicular cancer.