In the 1930s, science was really in its infancy. Almost nothing was known about genetics or even the fossil record. We had the basics, yes, but very little understanding and there were huge holes in our knowledge.
Today there is an overwhelming mountain of evidence in favor of evolution. Evidence comes from looking at the sequence of our own genomes and those of other species, from looking at the fossil record (bones of many intermediate species between humans and the ancestor we share with apes have been found in the past 70 years), and even from seeing how living organisms can evolve right before our eyes (short-lived creatures such as bacteria and fruit flies) all prove that evolution does indeed happen, and that there are many species that appear to be physically between humans and apes.
If you want to argue against evolution, get a degree in biology first. It's hard to argue with biologists when you don't actually seem to understand the evidence in favor of evolution.