human embryonic stem cells

An international team has put human cells into monkey embryos in hopes of finding new ways to produce organs for transplantation. But some ethicists still worry about how such research could go wrong.

A Swedish biologist wants to change the genes of healthy human embryos to find ways to treat infertility and other diseases. The experiments intensify ethical questions about genetic engineering.

Scientists have been able to keep human embryos alive twice as long as before. The technique is reopening a debate over a rule limiting research on human embryos to 14 days.

Researchers have found a way to mass- produce the pancreatic cells that are insulin factories inside the body. The findings could eventually lead to treatments that would transform diabetes care.