Authorities arrested a man trying to smuggle six vials of sperm into the country, a customs officer said Thursday, the latest sign that a commercial surrogacy industry is growing in the opaque communist country following curbs around the region.

The 25-year-old was arrested in the border town of Nong Khai with the tubes packed inside a nitrogen tank, according to a Thai customs officer.

“It was his 13th time smuggling (semen) through Nong Khai,” the official told AFP, requesting anonymity because he was not authorised to speak to the press.

Officials believe the vials were bound for a surrogacy clinic in Laos, an impoverished country that is quickly soaking up demand for the “rent a womb” business.

The boom in Laos, an authoritarian nation with no restrictions on surrogacy, comes after neighbouring Thailand and Cambodia clamped down on the industry  following a flurry of scandals and concerns about exploitation.