24 March 2014
ByAppeared in BioNews 747
Bonking Baby Boomers and the Future of Sex
Organised by the Society for Reproduction and Fertility
Roslin Institute, Easter Bush, Midlothian EH25 9RG, UK
Presented by Professor John Aitken
Wednesday 12 March 2014
The annual Society for Reproduction and Fertility's 'Sex in 3 Cities' lecture series was given this year by John Aitken, Laureate professor of biological sciences at the University of Newcastle, New South Wales, Australia, with the title 'Bonking baby boomers and the future of sex'. The first in a three-lecture series took place at the Roslin Institute, Edinburgh, with Nottingham and London to follow.
Professor Aitken began with an examination of female fertility, likening age-related fertility decline to a steep cliff rather than a gentle slope. He argued that IVF, originally intended to treat blocked fallopian tubes, has little effect on female age-related infertility. Rates of IVF success also decrease with age, with very few successful IVF cycles for women aged 42 and above.
He brought up the pattern of child-bearing in the !Kung tribe as an example of the lifestyle to which our genetics are tuned. In the !Kung culture, women on average have their first child at the age of 19, and then go through sequential childbirth and lactation until 35. He contrasted this with the period of 'cultural infertility' in women between the ages of 19 and 29 in Western Europe and Australia, where child bearing is often delayed till an average age of 30 and women have 1.6 kids on average. This demographic shift is generally seen when child mortality decreases.
This epidemiological and demographic data didn't really address the causes of age-related infertility in women or suggest why assisted reproductive technologies, along with IVF, would be ineffective at combating it. Professor Aitken repeatedly referred to the 'inflexibility' of human reproductive biology, which perhaps undervalues some of the medical achievements of reproductive technology.
Professor Aitken then went on to discuss male infertility in rather more detail. He gave some interesting background on the comparatively low sperm numbers and motility in the human species, describing human sperm as optimised for 'the distance not the sprint' due perhaps to the lack of coupling between human copulation and ovulation compared to other species.
He then addressed the genetic mutations in sperm and subsequently in embryos and children that rise with paternal age. Complex multigenic conditions like autism and mental illness are more common in the offspring of older men, and miscarriage also increases with male parental age, even though fertility does not show the rapid decline it does in women.
Despite all this talk of infertility, the human population is still huge and exponentially increasing. Professor Aitken discussed the incidence of unplanned pregnancies and abortion in different regions, concluding that there remained much to be done to increase the availability and use of contraceptives. There have been no big contraceptive advances since the invention of the pill in 1960s and that this is clearly overdue for a change. Pharmaceutical companies are not investing in contraceptive development. Professor Aitken talked about the work he has done with the Gates Foundation developing a more effective, less irritant spermicidal gel.
He concluded on the need to develop a better cultural framework for women to have children earlier in life without harming their career. Since biology is inflexible, society must change. Contraceptives also need to be more widely available, as the malthusian consequences of overpopulation are suddenly on the horizon of this small planet. The talk sparked plenty of audience debate, especially on the need for population growth control.
The lecture was a good introductory overview of the interaction of human reproductive biology and social influences on reproduction, though the causes of infertility and genetic damage were not discussed in scientific detail. The talk was however very well-delivered and the event was a good place to meet other people interested in debate on reproduction.