Have I dealt with this? You bet I have! We have a female Boxer who can jump over anything the size of a baby gate, and because of that had to install a 41" high gate between our living room and kitchen to keep the little homewrecker where she cant hurt anything when we leave the house.
We also have 4 cats, whose litter pans are in the basement, which is only accessible through our kitchen.
Obviously, if you cut pieces out of the gate, it will make it less sturdy, for the dog or the baby (as the case may be), so that's definitely not the way to solve the problem.
We got around the problem by mounting the gate about 4-5 inches off the floor. The cats can squeeze under it, but the sturdiness of the gate isn't compromised, so the dog (or the baby) remains where you want her, and stays safe.
It works like a charm, and even my 26 lb. Russian Blue can squeeze under it!
Give it a try.....it really works!