Long-term marijuana users are reporting debilitating vomiting and stomach pain, part of a mysterious but possibly rising condition linked to weed.

A dating app for sperm donors, a penis that was twice bitten, and a 70-year-old first-time mom — these just scratch the surface of the most bizarre medical stories of 2016.

People who are born with extra body parts may not even know it, like some women who have two uteri. Others, like double penises and a set of horns, are more obvious.

Lots of presidents are known for their achievements, massive failures, and deaths. For some, however, the chronic medical conditions they battled through their lives show another side to their stories.

A baby born with a rare condition that made her tongue too big for her mouth is finally able to smile after a surgery to reduce its size.

A 14-year-old with a rare genetic condition that causes his skin to blister and fall off still manages to inspire others with his refusal to succumb to his circumstances.

Social media is highly successful with helping researchers find clinical trial patients for rare diseases.

A 23-month-old toddler who has the rare Prader-Willi syndrome is permanently hungry, and requires constant care so that he doesn't "eat himself to death."

In recent years, big pharma has shifted its focus away from developing "blockbuster" drugs to developing "orphan drugs" for patients with rare diseases. Why?