Humans have always searched for ways to better themselves, and to that end, scientists are working not only on technologies to head off genetic predisposition to disease, but also enhancements such as synthetic blood substitutes to boost strength and endurance, and brain implants to improve concentration and information processing. But according to the Pew Research Center, the majority of Americans would not want brain or blood enhancements for themselves or their children. Most of 4,726 people surveyed were “very” or “somewhat” worried about technology-enhanced humans and believe the negatives outweigh the benefits for society. What’s more, respondents said enhancements were likely to further widen the divide between the wealthy and the poor.