The research overturns every assumption about risks of conception by older parents because it shows that the chromosomes in sperm, rather than eggs, are more likely to experience mutations. It turns out that the eggs women produce have constant, and rather low, rate of mutation at any age while the rate of such mutations increases steadily with age for men and their sperm.
It's a kind of genetic change that most people don't think about. Older fathers don't exhibit any of the conditions such as autism, nor do their ancestors, but their sperm mutate and pass along those mutations at conception. Most of these mutations are harmless, but many affects brain function.
The old adage than men can reproduce successfully at any age is simply wrong. As is the adage that women are nuts to make babies past the age of 30.
This information also touches broader cultural images, such as the old geezer with the young woman looking as if he owned the keys to the reproductive kingdom. Be careful out there ladies.
Swaziland suffers from a high rate of death from HIV infection which has left a generation of children who have to take care of themselves, or turn to their grandmothers for help.
The grandmother in the story is now caring for 11 grandchildren left by the deaths of three daughters from AIDS.
And she does so by walking for hours into the forest and clearing a patch of land, sowing marijuana seeds and tending the crop, hoping the cops won't bust her.
The behavior of Swaziland grandma dudes is expedient but also make evolutionary sense. Anthropologist Kristin Hawkes of the University of Utah has developed the "Grandmother Hypothesis" based on the behavior of Hadza hunter and gatherers in Kenya.
Post-menopausal Hadza women gather for their grandchildren and Hawkes has proposed that these contributions increase the likelihood that the children will survive and pass on genes. That hypothesis is supposed to explain the evolution of menopause, and it makes sense. All over the globe grandmothers pitch in when mothers and children need help, while grandfathers are less likely to do so.
In any case, we of the culture with the popular show "Weeds" on TV have no right to judge those hard working women in Swaziland, do we?