An article entitled "Evolution and the Human
Tail" by Dr. Fred D. Ledley appeared in the May 20, 1982,
issue of The New England Journal of Medicine. The publication
of this article apparently served as the source of a whale of
a tale, for newspaper articles based on Ledley's publication
appeared all over the United States. One of these articles which
came to our attention had a headline typically associated with
this story: "Baby's Tail Lends Evolution Support."
The article stated that "The birth of a child with a tail
is a rare glimpse of 'the relation between human beings and
their primitive ancestors,' a doctor says." Later on, Ledley
is quoted as stating that "Even those familiar with evolution
are rarely confronted with the relation between human beings
and their primitive ancestors on a daily basis. The caudal appendage
brings this reality to the fore and makes it tangible and inescapable."

Thus, the reality of the fact of evolution is
made tangible and inescapable, according to Dr. Ledley, by the
birth of a baby with a tail. This is indeed the final conclusion
stated by Ledley in his article. One needs only to read this
article, however, to learn that Ledley himself has admitted
that this may not be so. Earlier in the article (p. 1213), after
quoting Darwin who said that "We thus learn that man is
descended from a hairy quadruped furnished with a tail,"
Ledley states "When the caudal appendage is critically
examined, however, it is evident that there are major morphologic
differences between the caudal appendage and the tails of other
vertebrates. First of all, the caudal appendage does not contain
even rudimentary vertebral structures.… Secondly, the appendage
is not located at the caudal terminus of the vertebral column.
It is possible that this structure is merely a dermal appendage
coincidentally located in the caudal region. This possibility
cannot be excluded" (emphasis added).

How can it be said that the presence of this "tail"
brings us tangibly and inescapably to the reality of evolution
if we cannot exclude the possibility that it is nothing more
than a dermal appendage coincidently located in the caudal region?
As a matter of fact, even a superficial reading of Ledley's
article makes clear that this so-called tail was no tail at
all but was nothing more than an anomalous growth coincidentally
located in the caudal region.

Case Description

The infant was normal in every way except for
the presence of the appendage. The appendage was slightly more
than two inches long and had a diameter at the base of about
1/4 inch. It was located adjacent to the sacrum and was offset
from the mid-line about 1/2 inch. The appendage had a soft fibrous
fatty core and was covered with skin of normal texture. There
were no bony or cartilaginous elements in the appendage and
it was found to have no connection to vertebral structures.
X-rays of the spine were normal. The appendage was removed surgically
under a local anesthetic.

Ledley's Interpretation of the Appendage

The boichemistry of man is remarkably similar
to that of the apes and, in fact, is very similar to that of
all other living creatures (This is, by the way, precisely what
creation scientists would predict). What, then, accounts for
the profound morphological differences between man and the apes
and all other creatures? Obviously the differences do not reside
in the genes that code for proteins, but must reside in other
genetic characteristics.

In seeking to explain evolution, many evolutionists
are now suggesting that much of evolution is due to mutations
in regulatory genes, genes that do not affect the structures
of proteins but which are believed to control the temporal,
spatial, or proportional relations between developmental structures
and events. Ledley apparently believes that the human "tail"
results from such a mutation. Ledley states "In modern
theory the parallels between ontogeny and phylogeny derive from
the ability to trace the phenotypic expression [external morphological
change] of developmental mutations to specific stages of embryonic
development at which differentiation occurs between largely
homologous molecular and morphologic structures."

Later, Ledley goes on to say that "The modern
understanding of teratology [the study of anomalous malformations]
and tail formation finds nothing unhuman or reversionary about
the tail-like structure.…

The child with a tail is striking not because
the tail is a 'reversion' but because it is not a reversion—because
it is entirely consistent with our understanding of ontogeny
and phylogeny, which places us in the midst of primate evolution.
The occurrence of the caudal appendage, as well as the presence
of a well-formed embryonic tail in a child, are testimony to
the preservation of the structural elements necessary for tail
formation in the human genome."

What is Ledley saying? What he seems to be saying
is this: Although humans do not ordinarily have tails, and thus
the genes for tails in humans are usually suppressed, yet humans
still retain genes for tails—"structural elements
necessary for tail formation in the human genome." According
to Ledley, then, though the genes are not expressed and thus
are useless baggage, we humans for many millions of years have
been carrying those genes and faithfully reproducing them even
though they are totally without function.

Presumably, then, we would also be carrying along
in our human genetic apparatus other genes that are responsible
for all other characteristics seen in our monkey-like ancestors
but not seen in man. Following this thinking to its logical
conclusion, the human genetic apparatus should still be carrying
every gene ever possessed by any of our ancestors, even the
genes that make a worm a worm, if indeed a worm was the ancestor
of vertebrates.

Alternative Explanations

We would like to emphasize once again the fact
that this appendage was not a tail. We have already quoted Ledley's
own testimony that the "tail" did not contain even
rudimentary vertebral structures. Ledley states in his article
that there is no precedent for a vertebral tail without caudal
vertebrae. The "tail" was offset from midline with
no connection to vertebral structures and contained a soft fibrous
fatty core. The resemblance to a tail was highly superficial.

Ledley reports that there are at least 30 mutations
known in laboratory mice that affect tail morphology. Most mutant
tails contain caudal vertebrae, but a particular mutant frequently
has no caudal vertebrae, leaving a shortened boneless tail filament
containing only loose connective tissue, blood vessels, and
nerve fibers. Ledley compares this to the human "tail."
These two conditions are in no way comparable, however. The
normal mouse has a tail, and the mutant condition represents
the loss of a normal structure. The human has no tail, and the
caudal appendage represents the gain of an anomalous structure.
Furthermore, the condition in the mouse is unquestionably due
to a mutant gene and is, of course, inheritable. As Ledley states
in his article, however, the caudal appendage in the human is
a benign lesion which has never been reported to recur in families.
If this caudal appendage were due to a mutation, the mutant
gene would be passed on to offspring and would eventually be
reexpressed in some of those offspring. This has never been
known to occur. The anomaly is thus not due to a mutation but
to some disarrangement that occurred during embryological development.

Rijsbosch describes a similar anomalous growth
in a newborn male.¹ He refers to it as an "unusual
tumor in the sacrococcygeal area" with a core that consists
entirely of highly vascularized fatty tissue. He reported that
no osseous, cartilaginous, or muscular tissue was encountered
and that the structure was in complete accord with the caudal
formations in man described in medical literature. He reviewed
the myths that had been associated with these and other anomalous
growths, particularly in the Middle Ages.

Rijsbosch reviews a report by Schaeffer²
in which Schaeffer emphasized that "tail" formation
is not necessarily an isolated phenomenon but may be associated
with numerous other congenital anomalies. Schaeffer was able
to derive from the medical literature a list of 35 deformities
and anomalies which may exist concurrently with the caudal appendage.
If, as Ledley maintains, "some malformations may in fact
represent back mutations to an ancestral state" (see p.
1214 of his paper in The New England Journal of Medicine)
and the caudal appendage is one of these, we should also be
able to associate many of the 35 deformities reported by Schaeffer
with other ancestral states. No such relationship can be inferred,
however. These, as well as the caudal appendage, are nothing
more than anomalous malformations not traceable to any imaginary
ancestral state.

Rijsbosch also notes that M. Bartels³
had collected 116 reports of "tail" formation in humans.
In cases where the sex was reported, 52 were males and 16 were
females. If the caudal appendage represents a back mutation
to an ancestral state, the human male must thus be somewhat
closer to his monkey ancestor than the female since the condition
occurs three times more frequently in males than in females!

Warkany reports that while most persons with caudal
appendages showed normal general development, caudal appendages
have been associated with such malformations as meningocele,
spina bifida, chondrodystophy, cleft palate, hemangiomas, syndactyly,
hypodactyly and heterotopic anus.⁴ Can evolutionists
identify ancestral states with any of these malformations?

If malformations may possibly be due to the expression
of genes inherited from distant ancestors but long suppressed,
one can think of interesting suggestions. For example, some
human females are born with mammary glands under the armpits.
Some bats normally have their mammary glands in that region.
Does that mean that human females are carrying long-suppressed
genes for mammary glands under the armpits and we humans have
a bat in our ancestry? Some human females are born with mammary
glands in the groin region. Mammary glands normally occur in
the groin region of some whales. Does that mean that human females
still possess genes for mammary glands in the groin region that
have been inherited from a whale ancestor? Mammary glands, as
a matter of fact, have developed in humans in many places, including
the back, arms, and legs. How can evolutionary theory help us
explain that?

This paper in The New England Journal of Medicine
thus represents simply another contribution to the mythology
generated by the occurrence of malformations in the newborn.

References