ZIFT is very similar to GIFT except that fertilized embryos (zygotes) are transferred directly to the fallopian tubes. The advantages of both IVF and ZIFT is that the early stages of embryonic development can be established.

In GIFT there is no observable evidence that fertilization has taken place.

With ZIFT only fertilized embryos are transferred to the fallopian tubes so doubts about fertilization have already been resolved.