People With Situs Inversus Have Flipped Organs
If beauty lies in symmetry, a human's beauty is truly skin deep. That's because when you look past our visible features and delve inside our bodies, symmetry is the exception to the rule: your stomach and heart are on the left side, your liver is on the right, and your right lung has more lobes than your left -- for most people, that is.
Affecting as few as 1 in 20,000 people is a genetic condition known as situs inversus, where the internal organs are positioned in a mirror image to what's considered normal. This doesn't always happen with all of the organs at once: sometimes, it's just the heart that's flipped to the other side; other times several organs are flipped while others aren't. By itself, situs inversus doesn't usually cause harm, but it can come coupled with various other genetic conditions that can cause heart problems and other medical issues. The chances of a child being born with the condition are strikingly rare, but it does also happen with "mirror image" twins whose fertilized embryo splits late in its development.