A Merck & Co. sales representative is suing the drugmaker for at least $100 million, saying Merck doesn’t give women equal opportunities for advancement and punishes employees for taking maternity leave.

Kelli Smith, a Merck employee since 2004, says the company’s sales plans create incentives to discriminate against women, that women are told they have to choose between having children and taking bigger roles at the company, and that men get more opportunities to meet senior managers and develop important contacts.

Smith says she has won awards for her work but was unfairly demoted after taking maternity leave in 2010. She wants to create a class action lawsuit on behalf of Merck’s female sales representatives.

The Whitehouse Station, N.J., company did not immediately respond to requests for comment.