While some research suggests that autism contains a genetic link, most instances of the disorder remain unexplained. But now, researchers at Johns Hopkins University say predicting whether a child will develop autism may be as simple as testing paternal sperm.

In a small study, published online Wednesday in the journal International Journal of Epidemiology, researchers searched for a possible association between the disorder and a father’s epigenetic tags, which help regulate genes’ activity. Doctors can detect epigenetic changes by testing sperm.

"We wondered if we could learn what happens before someone gets autism," study author Andrew Feinberg, M.D., M.P.H., the King Fahd Professor of Molecular Medicine and director of the Center for Epigenetics at the Johns Hopkins University School of Medicine, said in a news release.

After studying 44 fathers’ epigenetic tags in 450,000 different positions throughout the genome, researchers identified more than 190 sites where the presence or absence of a tag was statistically related to whether the father’s child would show early signs of autism.

The dads had been participating in an ongoing study meant to assess how parents' biological data may influence their future children’s autism risk. The parents enrolled in the study already had a separate child diagnosed with autism.

The study collected health information from pregnant mothers who had a previous child diagnosed with the disorder, as well as data— including a sperm sample— from the dads. Researchers also drew biological data from the children after they were born but before they were potentially diagnosed with autism. One year after their birth, doctors assessed the children for early signs of autism using the Autism Observation Scale for Infants (AOSI).

When researchers analyzed which genes were near the identified sites related to autism risk, they found that 10 were located close to genes that are involved in developmental processes. Autism is marked by social and occupational issues related to development.

Of those 10, the four that were most strongly linked to the AOSI scores were positioned near genes of Prader-Willi syndrome, another genetic disorder that shares behavioral symptoms with autism. Researchers also observed that the altered epigenetic patterns were present in children already diagnosed with the disorder.

"If epigenetic changes are being passed from fathers to their children, we should be able to detect them in sperm," co-lead investigator, professor and chair of the Department of Mental Health in the Bloomberg School of Public Health, said in the news release.