“moral duty not to bring unwanted offspring into the world”
NO! The moral duty would be to be responsible and not get pregnant if you don’t want another child.
Children are not trash that you throw away because they don’t cenveniently fit into your plans!
Conveniently overlooking the illogic that her “unwanted offspring” would be eagerly adopted and loved by someone else. I would guess she would not dare to cover the waiting lists and travails of couples waiting to adopt “unwanted offspring”.