The inalienable right to life possessed by every human being is present from the moment of initial formation, and all human beings shall be entitled to the equal protection of persons under the law.
The Twinning Challenge
Bill Fortenberry
One of the challenges to the view that personhood begins at fertilization comes from the fact that twinning occurs after fertilization. This challenge is usually presented in the following manner:
"You say that fertilized eggs should be defined as people, but how can a fertilized egg be a person if it can randomly split and become two or more people through twinning? How can something be one unique person if it could also be two or more people?"
The solution to this challenge is to recognize that twinning is just a natural form of cloning.
Dolly was cloned from a cell in the mammary gland of an adult sheep, but the scientists in that experiment could have just as easily used a cell from a juvenile sheep or even from a newborn sheep. They could even have used a cell harvested from a sheep embryo. The results would have been the same regardless of the age of the donor.
In fact, there is no reason why Dolly couldn't have been cloned from a cell taken from a sheep in the blastocyst stage. All that is needed is a cell with the complete DNA of the donor, and this is present in every cell from fertilization onward. A clone taken from the blastocyst stage would be only a few days younger than the donor and could even, theoretically, share the same womb and have the same birthday. In other words, a clone of a blastocyst would share all the characteristics of a twin except that it would have been formed at the bequest of a human scientist rather than through a natural process.
Now, if we apply this back to the twinning challenge, we can see that one of the twins is the person that was conceived while the other is not. However, each one is still the same person as he was from the initial moment of his formation. The only difference between them is that one was formed through the process of fertilization while the other was formed a few days later through a process of natural cloning. They are separate and unique individuals who both have the same ethical standing as any other human being. That is, each of them is a person from the moment of his initial formation regardless of when, or how, that formation occurred.
"You say that fertilized eggs should be defined as people, but how can a fertilized egg be a person if it can randomly split and become two or more people through twinning? How can something be one unique person if it could also be two or more people?"
The solution to this challenge is to recognize that twinning is just a natural form of cloning.
Dolly was cloned from a cell in the mammary gland of an adult sheep, but the scientists in that experiment could have just as easily used a cell from a juvenile sheep or even from a newborn sheep. They could even have used a cell harvested from a sheep embryo. The results would have been the same regardless of the age of the donor.
In fact, there is no reason why Dolly couldn't have been cloned from a cell taken from a sheep in the blastocyst stage. All that is needed is a cell with the complete DNA of the donor, and this is present in every cell from fertilization onward. A clone taken from the blastocyst stage would be only a few days younger than the donor and could even, theoretically, share the same womb and have the same birthday. In other words, a clone of a blastocyst would share all the characteristics of a twin except that it would have been formed at the bequest of a human scientist rather than through a natural process.
Now, if we apply this back to the twinning challenge, we can see that one of the twins is the person that was conceived while the other is not. However, each one is still the same person as he was from the initial moment of his formation. The only difference between them is that one was formed through the process of fertilization while the other was formed a few days later through a process of natural cloning. They are separate and unique individuals who both have the same ethical standing as any other human being. That is, each of them is a person from the moment of his initial formation regardless of when, or how, that formation occurred.