There is zero implication that Peter was experimented on by his dad in the movie. That's something you're reading into the movie that isn't there. Plus, even if Peter's dad was experimenting on him, does that mean ANY animal that bit him would give him powers? So say he was bitten by a Chiuaua. Would he be able to yap at people super loud?
There's no way his dad would be able to forsee that Peter would break into a lab filled with gentically altered spiders at Oscorp 15 years later. That's just poppycock. Yes, I said it. Poppycock. Because the word is as ridiculous as the theory.










I don't think anyone bitten by a spider in the lab would get Spidey's powers. I think it's implied that the dad may have been experimenting with Peter and the spider bite was the final catalyst.