A study of recent birth patterns in the Southern California Region of the Kaiser-Permanente Medical Care Program (KPMCP) suggests that individuals may have been attracted to the Program by a liberal maternity benefit. The attraction is reflected in both the type of members joining KPMCP and the birth rate of those members. Although the KPMCP birth rate has been below that of the general population, new members in their first year of coverage delivered approximately one third of all KPMCP births in 1977, twice the number of births that would be anticipated from an equal number of members in the plan for one year or more. The maternity copayment of up to $350 did not deter women already pregnant from joining KPMCP. Termination rates for new members who gave birth, however, were no higher than expected. The Pregnancy Disability Amendment of Title VII of the Civil Rights Act of 1964, which became effective April 29, 1979, may alter the maternity benefits offered by alternative insurance carriers. The law could impact KPMCP’s enrollment and utilization of obstetric services.