An electrical connector includes: an insulative housing having a front tongue with two opposite surfaces; and a first and second rows of contacts with contacting portions exposed to the two opposite surfaces of the tongue; wherein the first row of contacts include a row of contacts from a first contact carrier of a first thickness and a row of contacts from a second contact carrier of a second thickness less than the first thickness; and the row of contacts from the first contact carrier and the row of contacts from the second contact carrier are molded to form the first row of contacts. A method of making a contact module of the electrical connector is characterized by molding the row of contacts from the first thicker contact carrier and the row of contacts from the second thinner contact carrier to form the first row of contacts.