Interfaith marriages are becoming increasingly common in Western societies. Your mom should consider herself fortunate she was able to evangelize your dad. It doesn't usually work out that way. Usually, it's a begrudging, "Well my wife is into it." It's not just the spouse, it's the family of the spouse. A pair of agnostic doctors meet in the hospital and fall in love. No problem? One is Jewish the other is Muslim--tense! Of course it can be overcome, but how does that reasonably play out?
There are a number of factors:
1. How do you see your ideal household? Church weekly or twice a year? Prayer in the home? Some atheists specifically avoid "Bless you" after a sneeze. Religious education, which might include Hebrew or Latin?
2. How involved with the church do you expect to be? Daily Mass? Rosary? Service projects? Family engagement events? The more involved you are, the more likely your child will grow up with faith. This has been my personal experience. My son, of an atheist mother, just said today, "Being Catholic is cool." Nice. We're church regulars.
3. How recalcitrant is your fiance towards involvement? Many spouses will go through the Rite of Christian Initiation in Adults to convert. This is about a fifty-hour process over a period of 6-18 months--definitely doable.
4. Will your spouse be happy if religion is thrust into his world and kids come home with crosses, rosary beads, and children's Bibles? An unhappy spouse is an unhappy family. Open communication is key. A Catholic priest will generally marry an interfaith couple as long as the understanding the children will be raised Catholic. But what if your fiance gets frustrated and bails? Your choices are to leave the Church, live in a state of perpetual adultery, or choose indefinite chastity.
5. Will your fiance feel comfortable attending events even if he remains atheist/agnostic? Churches are open to all. Just don't say the Creed if you don't believe it. Without involvement from your fiance, there will be an inherent inequity in your relationship, and the kids will get a mixed message.
In conclusion, I don't believe there is one simple answer. Kids absorb what you teach them. The more you teach it, the more they absorb it.