It is lawful for any physician or surgeon licensed in this state, when so requested by any person eighteen (18) years of age or over, or less than eighteen (18) years of age if legally married, to perform upon such person a surgical interruption of the vas deferens or fallopian tubes, as the case may be; provided, that a request in writing is made by such person prior to the performance of such surgical operation; and provided further, that prior to, or at the time of such request, a full and reasonable medical explanation is given by the physician or surgeon to such person as to the meaning and consequence of the operation.