What is infertility ? Explain IVF-ET and ZIFT methods to assist infertile couple to have children,

Explanation

The inability to produce children in spite of unprotected sexual cohabitation
IVF - ET (Invitro fertilization and Embryo transfer)
It is also called as test tube baby programme.
Ova from the wife or donor female and sperms from the husband or donor male are collected.
Sperms and ova are fertilized in laboratory to form Zygote.
Fertilization takes place outside the body of mother. Hence it is called invitro fertilization.
The 8 celled embryo could be transferred to the fallopian tube of surrogate mother.
ZIFT (Zygote intra fallopian transfer)
After invitro fertilization the Zygote is transferred into the fallopian tube.