NJ Rep. Chris Smith seeks to ban human-animal hybrids

Foreword: It is the opinion of this journalist that H.R. 2161, the Human-Animal Chimera Prohibition Act of 2025 is deceptively written in an effort to make it seem like it will not affect research involving transgenic animals. In this article I plan to lay out the information that I used to arrive at this conclusion.

On March 14th, 2025, Representative of District 4 of New Jersey, Chris Smith, introduced H.R. 2161, the Human-Animal Chimera Prohibition Act of 2025". The bill, in its own words, seeks to 'prohibit certain types of human-animal chimeras', in other words, it is a bill that would ban the creation of human-animal hybrids.

The bill's definition for a 'human-animal chimera' includes a variety of hypothetical creatures that wouldn’t be out of place in an episode of Black Mirror or The Twilight Zone. Some of the specified ‘chimeras’ include:

• “a human embryo into which a nonhuman cell or cells…have been introduced to render the embryo’s membership in the species Homo sapiens uncertain”

• “a human-animal embryo produced by fertilizing a human egg with nonhuman sperm”
• “a human-animal embryo produced by fertilizing a nonhuman egg with human sperm”
• “A nonhuman life form” which “contains a human brain or a brain derived wholly or predominantly from human neural tissues” or “exhibits human facial features or other bodily morphologies to resemble human features”.
• “An embryo produced by introducing a human nucleus into a nonhuman egg”

The full definition of what the bill considers to be a chimera can be found in the text of the bill itself.

It is unclear exactly who or what organizations this bill is aimed at, as most people would say that fertilizing an egg with sperm of a different species is impossible, and therefore does not require legislation banning it. Similar claims can be made about placing a human (or “human-like” brain) into a non-human body; many would say that it simply isn’t something modern science is capable of.
So one might be compelled to ask: Why does Representative Smith think this is worth the time and effort it takes to review and pass a bill?

It may have something to do with the recent national conversation around transgenic mice: For those unaware, On March 4th, President Trump claimed during his State of the Union that Former President Biden’s administration spent $8 million on “making mice transgender”, to which many citizens responded that he was likely misinterpreting a research study involving transgenic mice.

The National Cancer Institute defines transgenic mice as “Mice that have had DNA from another source…put into the nucleus of a fertilized mouse egg. The new DNA becomes part of every cell and tissue of the mouse. These mice are used in the laboratory to study diseases”. If you are interested in learning more about the history of transgenic animal research, I recommend this fascinating article by Forbes Science Contributor Kiona Smith.

Now it may become easier to speculate on what the goal of this bizarre piece of legislation may be: to limit or possibly outright ban the use of transgenic animals in the United States.

This interpretation, however, becomes muddled by a subsection called the Rule of Construction, which states as follows:
“This section does not prohibit research involving the use of transgenic animal models containing human genes or transplantation of human organs, tissues, or cells into recipient animals, if such activities are not prohibited under subsection (a)”.

On its face, it seems like this bill would have an exception for research involving transgenic animals, meaning its penalties would not apply to those engaging in such research. However, this exception has an exception of its own- “if such activities are not prohibited under subsection (a)”, meaning those performing research on transgenic animals that includes actions described in subsection (a) would still be beholden to restrictions and penalties.

Prohibited actions described in subsection (a) include:

• “(1) create or attempt to create a prohibited human-animal chimera;”
• “(2) transfer or attempt to transfer a human embryo into a nonhuman womb;”
• “(3) transfer or attempt to transfer a non­human embryo into a human womb; or”
• “(4) transport or receive for any purpose a prohibited human-animal chimera"

This, presumably, means that under this bill, researchers that engage in the creation, transport, or receipt of animals that meet the criteria of being “human-animal chimeras” would be subject to penalties including up to 10 years imprisonment. As stated above, one of the types of ‘chimera’ this bill would include in its definition are those that are created by introducing a human nucleus into a nonhuman egg.

Effectively, what this bill would do is conflate actual scientific practices with science fiction. It would put research that is nearly 50 years in the making, that has led to some of the biggest breakthroughs in medical history, in the same category as Frankenstinian, Chronenburgian nonsense.

What is still not clear is exactly why Representative Smith seems to be making this effort to ban a major avenue through which biomedical researchers test treatments and cures.

As of writing this article, I have reached out to Representative Smith as well as his Communications Director, Jeff Sagnip, for comment and have not yet received a response. This is a developing story and will be updated when new information is made available.