The Catechism of the Catholic Church:

2273 The inalienable right to life of every innocent human individual is a constitutive element of a civil society and its legislation:

“The inalienable rights of the person must be recognized and respected by civil society and the political authority. These human rights depend neither on single individuals nor on parents; nor do they represent a concession made by society and the state; they belong to human nature and are inherent in the person by virtue of the creative act from which the person took his origin. Among such fundamental rights one should mention in this regard every human being’s right to life and physical integrity from the moment of conception until death.”

“The moment a positive law deprives a category of human beings of the protection which civil legislation ought to accord them, the state is denying the equality of all before the law. When the state does not place its power at the service of the rights of each citizen, and in particular of the more vulnerable, the very foundations of a state based on law are undermined. . . . As a consequence of the respect and protection which must be ensured for the unborn child from the moment of conception, the law must provide appropriate penal sanctions for every deliberate violation of the child’s rights.”

2274 Since it must be treated from conception as a person, the embryo must be defended in its integrity, cared for, and healed, as far as possible, like any other human being . . . . 

Mayor Giuliani’s position:

“Giuliani supports loosening restrictions on federal funding of embryonic stem cell research and generally broadening such research,” The Pew Forum on Religion and Public Life.

“McCain and Giuliani were the only ones who said they would support embyronic stem cell research although they both hedged their answers by saying that was true only as long as cells weren’t being created for the express purpose of destroying them,” WaPo’s Politics Blog.

See also here, here, and here.    

And consider the following exchange between Giuliani and Chris Wallace of Fox News:

WALLACE: The reason I ask is when you were asked in the last debate about stem cells, embryonic stem cell research, you said you could support it except when it was a matter of creating a life to take a life.

The implication there seems to be that you think of that frozen embryo as a life.

GIULIANI: There are rights that have to be evaluated, and then . . . .

WALLACE: But can I ask you directly: Do you think of that frozen embryo . . . .

GIULIANI: I don’t look at it that way. I don’t think it’s for me to decide. I can’t decide when life begins. All that I can decide is, you know, what are the constitutional issues? What are the legal issues? How do you deal with these things?