Del. Code tit. 18 § 3575
A carrier offering a large group health benefit plan may not require any individual (as a condition of enrollment or continued enrollment under the plan) to pay a premium or contribution that is greater than such premium or contribution for a similarly situated individual enrolled in the plan on the basis of any health status-related factor in relation to the individual or to an individual enrolled under the plan as a dependent of the individual. This prohibition shall not be construed to restrict the amount that an employer may be charged for coverage under a large group health benefit plan or to prevent a carrier from establishing premium discounts or rebates or modifying otherwise applicable copayments or deductibles in return for adherence to programs of health promotion and disease prevention, if not otherwise prohibited by law.
18 Del. C. § 3575