Abortion is the issue that first brought evangelical Christians and other cultural conservatives into the arena of bioethics. Although today bioethics is dominated by other issues that are perceived as more pressing, the answer to the philosophical question lurking behind abortion--Who and what are we?--turns out to be the key that unlocks the ethical quandaries posed by these other issues. Aft...

1. The 'somite centres*. Spratt (1955) put forward the idea that two 'somite centres' exist in the chick blastoderm and that these actively induce the formation of somites. His evidence is based mainly on a series of transection experiments. 2. HenserCs node. This theory is based on the results of experiments in which the node is damaged or extirpated (e.g., Peebles, 1898; Wetzel, 1929; Fraser,...

there is great interest worldwide in discovering and developing a permanent source of tissues which would be capable of generating any cell type and which would avoid the problem of transplant rejection. stem cells are cells that can specialize into the many different cells found in the human body. the ethical objections concerning stem cells have focused primarily on their source. human embryo...

The majority of embryos created in natural reproduction die spontaneously within a few weeks of conception. Some have argued that, therefore, if one believes the embryo is a person (in the normative sense) one should find 'natural' reproduction morally problematic. An extension of this argument holds that, if one accepts embryo deaths in natural reproduction, consistency requires that one also ...