My Son's Project Is To Replicate DNA. It Has To Be Able To Stand Alone For Display?

Use a flat object like a block of wood then you can drill small holes for the strands of dna and hot glue them in...

That's a tricky one but I'll have a go. Take a hollow transparent tube, the tube should be fractionally larger than the diameter of two M&M's. Fill the tube with M&M's which will represent the base pairs of DNA, one opposite another but that will be difficult with M&M's, shake the tube until it looks more or less like they are one opposite another. The take some electrical cable and make a spiral coil along the length of the tube. Then make another spiral exactly opposite and going in the opposite direction. The two coils will represent the double helix of the DNA. There you go, you will no doubt have to spend some time making it look somewhat as it should do. In real life there isn't a central tube, the whole thing is held together by hydrogen bonding between the base pairs.