The antonyms for the term "Zygote Intrafallopian Transfers" would vary depending on the context. As a medical technique of assisted reproduction, antonyms might include natural conception, sperm and egg donation, or adoption. In terms of the actual words involved, antonyms for "zygote" might include "adult", "fully-formed", or "mature", while antonyms for "intrafallopian" could include "extrauterine", "intrauterine", or "non-tubal". Lastly, antonyms for "transfers" could include "removals", "withdrawals", or "subtractions". However, it is worth noting that antonyms also have synonyms and related terms, and these may be more relevant in certain situations.