Pham Huy Quang, 43, Vu Thi Lieu, 29, and Pham Thien Tuan, 21, organized six cases of surrogacy since April, earning hundreds of millions of dong from them, they said Wednesday.

On Quang’s instructions, Lieu would find on social media women who wanted to be surrogate mothers for a payment of VND200-220 million ($8,600-9,500).

The trio would take care of all the expenses related to their pregnancy and delivery.

When they found someone seeking a surrogate mother, Quang would offer to find one for around 550 million (23,700).

Twins would cost an extra VND50 million while single males who want a kid would have to pay another VND10 million.

Vietnam legalized surrogacy in 2015 but only to benefit infertile couples and by family members. Commercial surrogacy is punishable by up to five years’ imprisonment.

Last week two women were arrested in Quang Ninh Province, three hours drive west of Hanoi, for illegally running a surrogacy ring for profit.

In April, police in Quang Ninh also arrested two women who ran an illegal surrogacy ring which took Vietnamese women to China to deliver babies.

For years now poor women have been lured to sell their newborns to China.

China, the world’s most populous country, suffers from one of the most skewed gender rates in the world due to its one-child policy and illegal abortion of female fetuses.

This has also been a major reason for the trafficking of Vietnamese women and girls over the border.