You could simply sterilise people (storing their sperm/eggs just in case). Sure, it sounds inhumane, but then that kind of appropriate if you want to survive in such an inhumane environment as is Mars.
There are long-acting contraceptives like IUDs and implants which, as a bonus, come with a near-zero failure rate. Quietly include a few just-in-case pills to account for the 0.05% failure rate (https://www.cdc.gov/reproductivehealth/unintendedpregnancy/p...) and hope the religious right doesn't get wind.
Well, that's one way to solve the problem. However, I think your "religious right" could maybe be convinced to fund space missions to support the survival of the first whoopsie space baby. Some of the major churches pull in a billion/week. A guy can dream....