That would illegalize thousands of abortions alone. So killing a mother and her baby near full term would only constitute one crime and not a second?

From a legal aspect:

Criteria for personhood
The above points seem to indicate that there may be persons that are not human, and there may be humans that are not persons. For these reasons, many philosophers have tried to give a more precise definition, focusing on some trait or traits that all persons, real and hypothetical, must possess.

The most obvious such trait that persons typically possess is a conscious mind, typically (but not necessarily) with plans, goals, desires, hopes, fears, and so on. Yet the claim that such a mind is necessary for personhood is also problematic, as most would consider human babies as persons, yet their minds do not seem sufficiently advanced to satisfy this condition. A few philosophers have simply accepted that babies are not persons. However, most have not. Instead, some have suggested that the potential for such a mind is the correct trait.

Yet another view is that personhood is not all-or-nothing: there can be degrees of personhood, based on how close to a fully working mind the object in question has. Thus, a typical adult is entirely a person, while a human permanently in a coma is not a person at all. This view also seems to have some unpleasant consequences, for example, that a young child or someone with a moderate mental handicap might be, say, only half a person (and perhaps therefore have only half the rights, or be regarded as half as important). Jean Vanier, who has spent most of his life working and living with people with learning disabilities, has suggested that the capacity to be loved is what makes a true person.

It is probably true to say that other views also exist, and that the debate is not close to being resolved.

http://encyclopedia.laborlawtalk.com/Person