The British Andrology Society is a learned society, with over 100 members, that focuses
on current issues of particular relevance to the reproductive biology and health of the male. Its
members include research scientists with active research programmes in aspects of male
reproduction in humans and other species, as well as clinical andrologists and embryologists
working both within the UK health sector itself and at the interface between research and clinical
practice. The society disseminates scientific information through its conferences, but also takes
an active role in setting national standards for clinical andrology practice. It is also concerned
about the translation of research into benefits for society, and about the impact of legislation and
regulations on the ability of those working in research to deliver effectively.
The draft Human Tissue and Embryos bill potentially impacts on several groups of our members
as some work with human sperm, oocytes and embryos in the clinical setting while others are
engaged in fundamental research on the basic biology of human and animal embryonic development.
Our members have expressed general disquiet about the imposition of additional licensing requirements for some of their research and diagnostic procedures, especially where those
involve the mixing of human and animal gametes. The specific point to note is:
Paragraph 3(2) of the new Schedule 2 will make it necessary to have a licence to conduct a zona
free hamster oocyte penetration test. This is a diagnostic test aimed at evaluating potential
infertility problems in men. In essence, hamster oocytes are denuded of their zonae pellucidae
(the outer coating of the egg) and mixed with patients’ spermatozoa. This is a functional test that
provides more information than routine evaluations such as sperm concentration and sperm
motility or morphology. Semen samples that fail to penetrate these hamster oocytes are more
confidently regarded as infertile.
Our concern is that in response to the need for an additional licence to perform this test, most
practitioners would simply see it as no longer worth the effort. Cheaper alternatives to the use of
hamster oocytes are also currently under investigation. These include the use of porcine oocytes
which are readily available from local abattoirs. Research groups that have investigated this
system as a functional assay for human sperm quality feel that it could provide a practical
functional test. However, the need for a licence might dissuade them from pursuing this line of
research which could ultimately benefit society.
It is worth stressing that neither the penetration of hamster nor porcine eggs by human
spermatozoa would result in a viable embryo. Chromosomal incompatibilities between the
species mean that the penetrating spermatozoa may form pronuclei, but that no further
development is possible. It is also the case that when hamster eggs are penetrated by human
spermatozoa, multiple spermatozoa enter the egg cytoplasm thus creating a polyspermic zygote.
Such a zygote produced from homologous sperm entry would be unable to develop, thus
providing a further level of reassurance that the inter-specific zygote would not develop beyond
Prof. William Holt
Institute of Zoology
Zoological Society of London
London NW1 4RY