Genetic Engineering

For an "Opposing Viewpoints" book Genetic Engineering (073773857X), I saw that we have some "genetic engineering" books in the following places:

• 174.2 for occupational ethics related to medical professions
• 174.28 for occupational ethics more specifically related to "experimentation" within medical professions
• 174.957 for bioethics
• 174.9574 ?
• 174.966 for ethics related to chemical engineering and related technologies
• 303.483 for "Development of science and technology" under social science "social processes"
• 306.46 for "technology" under social science "culture and institutions"
• 660.65 for "genetic engineering" as a part of biotechnology under chemical engineering and related technologies

There are even more! The most common numbers seem to be 660.65 and 174.957. It would seem to me that books that are simply descriptive would fall under 660.65 and that books like this one that are aimed at "pro/con" discussions would go in 174.957 and so I'm using 174.957. Having said that, I think this topic is pretty messy across the board.