Judge Vrushali Joshi found Mehndi Kasim, arrested in 2010, guilty of rape, causing miscarriage and criminal intimidation.
A total of 37 witnesses deposed in the court, including the seven victims, who are cousins, and their mothers.
According to the prosecution, Kasim knew a family where all four sisters have mentally challenged sons apart from (normal) daughters.
He promised to cure the boys and asked their mothers to send to him their daughters to him as well for 'treatment', so that they don't give birth to mentally challenged sons in future.
He used to give them spiked beverages before raping them. The prosecution also said that he aborted foetuses of two girls when they became pregnant.
Accepting the prosecution's case, the court today convicted Kasim and sentenced him to the life imprisonment.