Noun
an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life
Source: WordNetOne-third of all female infertility is the result of blocked fallopian tubes. If fertilization could be done in the lab and then the fertilized egg implanted in the womb, it would get around that problem. Millions of women who cannot have children would suddenly be able to. James D. Watson
The egg of every species of animal or plant carries a definite number of bodies called chromosomes. The sperm carries the same number. Consequently, when the sperm unites with the egg, the fertilized egg will contain the double number of chromosomes. Thomas Hunt Morgan