the sperm and egg whose union brings a human being into existence are not complete organisms. They are both functionally and genetically identifiable as parts of the male or female parents.

“The development of a human being begins with fertilization, a process by which the spermatozoon from the male and the oocyte from the female unite to give rise to a new organism, the zygote.” ...

The chromosome associated with male development, which is the last mysterious piece of the human genome, has been fully sequenced ... guide the development and function of all cells in living ...