They didn't make reproduction illegal. They confirmed that Monsanto's patent lets them restrict how you can use the products of reproduction (beans/seed).
These beans wouldn't naturally exist if it weren't for Monsanto. It would be extremely difficult to produce a soy bean that didn't produce seeds... since that's the bean part.
This is very different from the Myriad BRCA1 patent where they patented a naturally occurring mutation in humans. In Monsanto's case, they actually produced something that was novel - an herbicide resistant soy bean.
