While no source is likely to have perfectly unbiased information on a controversial subject such as genetic engineering, here are some good sources to use for something like this:
-Government mandated sources, such as websites that end in .gov or those that come from similar sources.
-Sources that have extensive research behind them, such as thesis papers from colleges. Good websites to use in this category usually end in .edu
-Articles from trusted sources, such as National Geographic, which have previously published articles based primarily on facts.
If you have any specific examples, I can help you determine which are reliable and which aren't, if you need.