In the current debate, we witness a conflict between the Christian concept of man vs. concepts that justify in vitro fertilization (IVF), genetic enhancement, or the reassignment of sexuality. Modern concepts cannot disregard the historic perspective of the consistent doctrines that the Catholic Church has maintained throughout her 2000-year history and which constitute the precursors of contemporary bioethics. Although she has adjusted specifics occasionally to address new developments, she has always based doctrine on immutable core principles. The current conflict lies neither in the novelty of the new proposals, nor in a conflict between religious and lay worldviews, but rather in concepts of man and human perfection. Some human traits may be regarded as disordered and incompatible with a particular concept of human perfection. The new proposals tend to involve physical changes based on technological manipulation, with a goal of developing a superior being, while Christian proposals do not seek to manipulate man’s being, but to develop his existing potential within criteria of acceptable reason. The new proposals rely on a Cartesian view which constitutes a human as his mind (cogito ergo sum), which has dominion over his body including authority to reengineer it according to any project that mind conceives. In contrast, the Christian concept views the human subject as a unity of mind and body, which may not be reshaped to meet a questionable goal of human perfection. The technological tools within the new concepts are in no way superior to the more personal attributes like virtues, perfection of the human will, prayer, and ascesis within the Christian concept.