18 | New Scientist | 22 February 2020
LAST year, researchers in China
announced they had inserted a
human brain gene into monkeys.
These 11 monkeys outperformed
typical monkeys in tests of
short-term memory, and their
brain development more closely
resembled that of humans.
Are these animals still fully
monkeys? Or are they something
else? Something human?
Plenty of other experiments
have blurred the line between
what is human and what isn’t.
Research teams have created
pigs with human genes. Clumps
of human brain cells have been
grown in dishes, and the cells can
communicate with each other.
Then there are “synthetic human
entities with embryo-like
features” – structures made
from human stem cells that
look like early embryos.
Should all these entities be
protected by law in the same ways
humans or human tissues are?
Some researchers think so, and are
proposing a new legal definition
for such entities: “substantially
human”. If the entity is more
human than not, it should be
granted human rights, they say.
But this raises questions as to how
exactly we define humanness, and
what that means for entities that
fall outside that definition.
It is only a matter of time
before we will be forced to decide,
say Bartha Knoppers at McGill
University in Montreal and Hank
Greely at Stanford University in
California. “At some point, courts
will be faced with the questions:
is this tissue human or not? Are
these remains human or not? Is
this living organism in front of
us human or not?” says Greely.
He and Knoppers suggest that
the term substantially human
could be applied in cases where
the line is blurred. “It means that
just because something is not100 per cent traditional human,
he or she should still be viewed
as human for purposes of human
protections,” says Greely.
The pair are being intentionally
vague. Whether an entity is
substantially human or not
should be a judgement call to be
made by individual countries.
The decision could be influenced
by a nation’s culture and values,
in the same way that the law uses
terms like “unreasonable” or
“best interests” without precisely
defining them, they say.
Others think we need firmer
guidelines. “Rules that include the
word ‘substantially’ are never fully
satisfying,” says Jeantine Lunshof
at Harvard University.
Inevitably, some will want
to come up with a test of – or at
least a guide to – humanness.
One starting point might be the
genome. Our genes certainly
make us human, in terms of
coding for human features. But
when we take a closer look, therearguably they are outside it,”
says Greely.
He worries that such criteria
could be used to argue that
some individuals aren’t fully
human. “Our species has an
often-expressed willingness
to find and magnify minor
differences amongst ourselves
into sources for hatred and
discrimination,” he says.
Instead, we need to think about
what makes humans “morally
significant”, says Julian Savulescu
at the University of Oxford.
“The idea of something being
‘substantially human’ is a step
forward because it shows there
isn’t a bright line between human
and non-human,” he says. “But
I think we’ll have to go further
than that and start to think
about the properties that are
especially valuable.”
Such traits are thought
to include things like self-
consciousness and the ability
to form complex relationships,Medical ethicsVICTO
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I, human
Researchers are blurring the lines of what it means to be human,
so do our laws need to change, asks Jessica Hamzelouis a lot of similarity between a
human genome and that of a
chimp, for example – or other
animals, for that matter. We share
97.5 per cent of our genes with
mice, according to one estimate.
However, genes alone can’t
determine legal status. Embryos
are genetically human, but in
most countries an early embryo
doesn’t have the same rights as
a baby. The same could be said
of human cells cultured in a lab.On the other hand, gene-edited
people like the three CRISPR
babies born in China are very
much human, even if they
have newly introduced genetic
mutations. “If you take a gene-
centred view of humanity,97.5%
Estimated percentage of genes
humans share with mice