ICSI involves injecting a single sperm directly into an egg and then transferring the resulting embryo into the uterus. This method bypasses the fallopian tubes entirely and is effective for cases of tubal blockage. However, since ZIFT also involves transfer to the fallopian tubes and would not be suitable in the case of blockages. GIFT, which requires functional fallopian tubes for the gametes to meet, would not be effective in this scenario, and IUI is similarly ineffective as it does not address the issue of blocked tubes.

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