What is fertillity? How infertillity is treated by assisted reproductive technologies like IVF-ET and ZIFT?

Explanation

Infertillty is the inability to produce children inspite of unprotected sexual co-habitation.
Infertile couple (Male// female) could be assisted to have children, through certain special techniques commonly known as Assisted Reproductive Technologies ( ART).
In vitro fertilization ( IVF- fertilization outside the body in almost similar conditions as that in the body) followed by embryo transfer ( ET) is one such method.
In this method, popularly known as test tube baby programme, ova from the wife// donor (female) and sperms from the husband//donor (male) are collected and are induced to from zygole under simulated conditions in the laboratory.
The zygote or early embryos ( with up to 8 blastomeres) could then be transferred into the fallopian tube. In zygote intra fallopian transfer ( ZIFT) the zygote is transferred into the fallopian tube to complete its further development.