Further to the discussion on menopause:-
Women are not the only gender to outlive their fertility. While there are
obvious and well-publicised exceptions, male reproductive capacity declines
with age but is not as catastrophic as female menopause. This decline
includes declining sperm output, abnormalities in the testicular
architecture, increasing levels of epididymal duct blockage (50% in men
over 50 years!) vascular changes including ischaemic damage and arterial
hyalinosis (the testicular artery is reputed to be one of the the first
sites in the body to demonstrate age related atherosclerosis), and
connective tissue changes. I have recently reviewed this field (Cummins
JM, Jequier AM, Kan R 1994: Molecular biology of human male infertility:
links with aging, mitochondrial disorders and oxidative stress? Mol Reprod
Devel 37: 345-362) and would be happy to enter into discussion on this. We
have also demonstrated that some forms of infertility are associated with
unexpectedly high incidence of mitochondrial DNA deletions ..... but
that's another story. As for impotence: well most authorities agree that
about 50% of men experience partial or total erective dysfunction by their
mid 50s.
The basic point is that as a species both male and female humans have
evolved to a state where they outlive their fertility.
Yours, virtually:-
Jim Cummins
Associate Professor in Veterinary Anatomy
Murdoch University,
Murdoch Western Australia 6150
Tel +61-9-360 2668
Fax +61-9-310 4144
E mail cummins at possum.murdoch.edu.au
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