「吐火獸」是古希臘神話中具有獅頭、羊身及龍尾之一種吐火怪獸，其乃嵌合多種動物於一體之生物。近年因生物科技及複製技術快速發展，生物複製態樣已非僅止於單純之自體複製生物，現實社會中已可見人類和其它動物之多樣化嵌合生物產生，因而被稱之為「現代吐火獸」或「人獸嵌合生物」。例如，背上長出人類耳朵之老鼠、具有人類頭腦基因之猩猩、以及日後可能產生之具有猩猩肌力基因之人類等。 傳統以來，胚胎幹細胞及複製等行為雖然可能對醫療研究有所助益，然而卻有相關宗教、道德、法律等議題之嚴重爭議，對於自體複製生物之規範至今尚無一致之理論見解，亦無完整之規範政策。人獸嵌合生物之出現益形使生物科技所遭遇之挑戰複雜化。 欲探討人獸嵌合生物，除了先必須回顧討論胚胎幹細胞及複製等基礎行為所面對之宗教、道德及法律等問題，及其對自體複製生物之相關規範政策，以檢討出對人獸嵌合生物應有之規範政策；繼之，本文主張應進一步研析此標的物之可專利性。因為，若干種類之人獸嵌合生物應可能為宗教、道德及法律等規範所接受，而要使其納入現今市場機制，必須有相關專利法規範之保障。 目前國內雖有文獻提及如背上長出人類耳朵之老鼠等複製情形，但並無針對人獸嵌合生物做有系統之相關法律見解，更無從專利法角度對之進行研析，本文主張對此應建立明確道德標準規範以期訂定法律規範，而且應修訂相關專利法條文以為因應。故擬於第二部分先將生物科技做一介紹，其包括幹細胞及複製、人獸嵌合生物之產生等。繼之，第三部分探討人獸嵌合生物相關之理論及法律爭議。第四部分為對美國及加拿大之比較法觀察及分析。第五部分針對人獸嵌合生物之可專利性進行討論，其包括法定標的、新穎性、非顯而易知性、實用性、及揭露充分性等。第六部分為結論。

The chimera of ancient Greek mythology was a fire-breathing beast with a lion's head, goat's body, and dragon's tai1. It was once merely the fantastic creations of science fiction, however, rapid advances in stem cell research and cloning which create “modern chimeras," have resulted in the blurring of species lines, including our own species, homo sapiens. In light of the fast-developing biotechnology and its foreseeable impacts, we should commence to regulate such modern chimeras in a comprehensive manner, especially when we had strategically embraced biotechnology, declaring it to be one of Taiwan's major industries for the years to come. To analyze modern chimeras, an issue deriving from general biotechnology arena would be feasible to start with, i.e., what are the ethical considerations to the existence of modern chimeras. Then, the underlying philosophical doctrines should be reviewed to appreciate why countries in the world set forth various policies to deal with these chimeras, without moving any closer to a harmonization. Further, issues as to how legislation and judicial system should react to these problems are to be studied, such that a tentatively regulatory framework may be envisioned. Finally, how patent law should regulate these chimeras is nevertheless a very important issue as well. And, the scope of discussing in this issue is focused on its patentability. This article seeks to address a clear ethical principle and sources of legal powers should be established to set forth necessary regulatory policies, and based on that, a suggestion of modifying the Patent Law to meet the demand from various communities in our country. In this article, Part II provides an overview of stem cell biology, wherein the status of stem cell research and the creation of modern chimeras are introduced. Part III identifies the debate over modern chimeras in the context of ethical, philosophical and legal arguments. Part IV comparatively studies the regulatory policies of modern chimeras in the United States and Canada. Part V analyzes the patentability of modern chimeras in terms of the statutory subject matter, novelty, nonobviousness, utility, and disclosure. Finally, Part VI offers a conclusion.