Hi there! Ill give you question a shot!
Firstly, A Patent "is a set of exclusive rights granted by a state (national government) to an inventor or their assignee for a limited period of time in exchange for a public disclosure of an invention". For example, the design of the Martin ejector seat of the military aircraft is covered under patents so that no one else, during the patent duration, can copy the designs - like copy-writing written work.
As for ethical issues... patents can reduce the amount of progression of a product for it sets narrow parameters on who can access and use new technologies. "To date the broadest and most controversial application of GMO technology is patent-protected food crops which are resistant to commercial herbicides or are able to produce pesticidal proteins from within the plant, or stacked trait seeds, which do both".
If I remember correctly, you can look up biologist Drew Endy on Fora.tv or Youtube.com, who talks about ethical issues concerning such patents ...
YouTube - Synthetic Biology: Drew Endy
Hope this helps!
