The sun makes me sneeze. It's not like I get fits of uncontrollable sneezes as if I'm allergic to the sunrays. But watch me leave a movie theater at high noon on a cloudless Saturday, and you can bet a large sneeze will explode out of my body within 30 seconds.

Since childhood, I thought sun sneezes were a malady that everyone encounters. But a few years ago, I explained to my then-boyfriend and now-husband that I could force a sneeze to happen by staring at the sun. His quizzical look revealed that sun sneezes are not normal. I'm an exception to a rule — but I'm not alone.

My light-induced sneezes are caused by a seemingly harmless disorder called "photic sneeze reflex." The Greek philosopher Aristotle referenced the phenomenon during the fourth century B.C., but wasn't until 1954 that scientists first described it in medical literature. Some researchers have since applied the appropriate acronym ACHOO: Autosomal Dominant Compelling Helio-Ophthalmic Outburst Syndrome.

An estimated 10 to 35 percent of the population has a photic sneeze reflex.

"It's not a disease," University of California, San Francisco neurologist and human geneticist Louis Ptáček told the NewsHour. "Some people find it annoying, but some people like it to some extent. They'll say, 'It helps me get a sneeze out.'"

The disorder is characterized by a sudden outburst of one or multiple sneezes when a dark-adapted person — they've been in a darkened space for a while — is suddenly exposed to light. Sunlight is a trigger, but artificial illumination from light bulbs and camera flashes can also cause sneezes. Additionally, a not-yet-established length of time in a darkened space — called a refractory period — must pass before an individual with photic sneeze reflex will sneeze in light again.

As it turns out, an estimated 10 to 35 percent of the population has a photic sneeze reflex. Because its prevalence is higher in individuals with a family history of the disorder, the handful of scientists who have studied the phenomena suspect a genetic, autosomal dominant — a person needs only one parent with the condition to inherit it.

Ask your parents about ACHOO

A regular sneeze is a violent preemptive strike. It is a reflex meant to protect the nasal passages and lungs from infectious agents or irritants. An estimated 40,000 microscopic particles can spew out of the human body — at a rate 85 percent the speed of sound — each time we sneeze. How delightful.

"When we sneeze, there is a huge contraction of the diaphragm all at once," Ptáček said. "Dust or black pepper particles in the nose, for example, irritate the mucosa and leads to a sneeze reflex to prevent you being hurt by a noxious environment."

But why did evolution decide for some of us to sneeze when accosted by bright light? Is it a forceful warning to keep my pale, Scottish skin from the sun's burning rays? (Answer: Likely, no.)

The most prevalent theory postulates that neurological signals are crossed between the trigeminal nerve, which senses facial sensations like an itchy nose, and the optic nerve, which constricts the eye's pupils when light penetrates the retina.

But large, in-depth studies on this or other theories are lacking, with most photic sneeze reflex research based on small case studies of single families or small groups of photic sneezers.