Section 8E. No contract between a subscriber and the corporation under an individual or group hospital service plan which shall be delivered or issued in the commonwealth shall be denied, cancelled or fail to be renewed, nor shall any excessive rates be charged or restrictions on the length of coverage be imposed, nor shall any other factor be altered in such a way as to constitute discrimination primarily because the insured person has had a suspected, alleged or confirmed exposure to the potential hazards and afflictions of diethylstilbestrol or compounds commonly referred to as DES. The practices prohibited under this section shall include not only those overtly discriminatory but also practices and devices which are fair in form but discriminatory in practice.