"Do your homework," said yoga guru Baba Ramdev today to opposition lawmakers who have alleged in Parliament that an ayurvedic concoction available at a pharmacy he runs seems to promise that it can help give birth to a male child. "Through me, a fakir, they are trying to malign Prime Minister Narendra Modi," he said, dismissing as an "unnecessary controversy" the furore in the Rajya Sabha yesterday over his 'Putrajeevak Beej' which translates to "the seed that gives life to a son."