Conception & Development
Conception
The moment when the egg and the sperm unite is called conception.
Generally conception occurs in the upper half of one of the fallopian tubes the egg is travelling through.
Conception can take place from about 72 hours before ovulation to about 48 hours after ovulation. If sperm is present in the fallopian tube during this time conception may occur.
Once the egg is fertilized it continues to move through the fallopian tube toward the uterus. When the egg reaches the uterus it attempts to attach itself to the uterine lining. If the fertilized egg does not successfully attach it will not survive.
About 20 hours after fertilization the nucleus of the sperm ('brain
of the sperm') fuses with the nucleus of the egg forming a single
cell called a zygote with the same basic cellular chemistry as all
other living things.
Development
Click here for information about pre-natal development in our Pregnancy section.