In mammals, what is the beginning of the life cycle?

Question

In mammalian biology, does life begin when the sperm cell fertilizes the egg cell, when the offspring are actually born, or some other event?

Answer 1

it's a cycle...

where does a ring start?

and if this IS a question about abortion.. BIOLIOGY isn't the place to be asking it.. you want PHILOSOPHY

Answer 2

Um, there's really not a beginning to a life cycle.  The egg and sperm are both living cells, which came from living tissue, which came from an organism which came from a living sperm and a living egg.

So, the beginning of the life cycle would then be the beginning of all life some 4.4 billion years ago.

Even the cells in your spit are living.  They'll probably die soon, but they're alive and genetically human.

Also, if this question is about abortion.  I'd recommend against it at the point when the nervous system forms.  There's no real reason for that, other than the organism would definitely experience pain.

Answer 3

Life begins with a sperm and an ovum