If you don't believe in Christianity, don't do it. When your children are older they can be baptised as adults if that is their wish. Although I did have DS Christened, DH and I are Christians and I disagree with people having Christenings because it's the "done thing" or they want a nice photo time and party. In a Christening, you are promising to bring your child up according to Biblical principles, to take your child to Church and to encourage Christian study and lifestyle. If you can't promise that, with sincerity, in a Church, no-one should ask you to.

Point out that it's far more of a sin to lie to God in this way than it is to not have your child Christened. HTH.