Well this made the news recently...
human-flesh-found-in-chinese-health-pills
...though the Chinese authorities are disputing that the reports are genuine...
China-ministry-Probe-finds-no-flesh-pills
It's probably worth pointing out that Chinese regulations on the disposal of aborted foetuses are stricter that their Western equivalents, as they are treated as human remains, not medical waste.
Using human fertiliser is broadly okay, but there are risks involved, mainly due to improper or incomplete composting of the waste before use. Harmful pathogens such as E.coli and Cryptosporidium can contaminate food grown in manure, and in the past fresh produce contaminated with human waste was a major contributor to the spread of typhoid.
Sewage sludge from municipal sources is usually pretty extensively treated, but often still needs to be 'incubated' to kill off any harmful pathogens. Ironically, this same incubation is known to increase the availability of metal contaminants in the sludge, which may lead to contamination of groundwater or river resources.
"Does Organic Gardening Foster Foodborne Pathogens?"
- RV Tauxe, Journal of the American Medical Association, 277:1680 (1997).
"Land application of sewage sludge: physicochemical and microbial response."
- RP Singh et al, Review of Environmental Contamination and Toxicology, 214:41-61 (2011).
"Potential benefits and risks of land application of sewage sludge."
- RP Singh & M Agrawal, Waste Management, 28:347-58 (2008).