BEIJING, May 6 -- A campaign began in April to clampdown on illegal prenatal gender tests and sex-selective abortions to address the gender-ratio imbalance, health authorities said.

According to the National Health and Family Planning Commission (NHFPC), the campaign, which will run until November, will concentrate on medical, health and family planning institutions, as well as illegal fertility agencies, clinics and itinerant physicians.

Gender tests on fetuses and sex-selective abortions are a crime in China. Nonetheless, the preference for sons, and family planning legislation have driven both practices.

There were 115.88 boys born for every 100 girls in 2014. The 12th Five-Year Plan set a target of 115:100 to be achieved by 2015.

China has the worst gender imbalance in the world. The NHFPC said this was a direct result of illegal pre-birth gender tests and sex-selective abortions.

The new campaign will tighten controls on medical equipment and medicine used in both procedures, and blacklist any organization found to be complicit in either activity.