The nature-nurture debate rages on, especially now that Simon Baron-Cohen is claiming that Autism is associated with masculinity because autistics are systematizers and males are systematizers, while females are empathizers.
This is mostly based on speculation and big stretches, that are effectively countered by the work of Elizabeth Spelke.
But it is indisputable that more boys than girls are autistic, with estimates ranging from 4:1 to 10:1.
It is also indisputable that infanticide was practiced far and wide througout human history, but especially female infanticide:
Infanticide has been practiced on every continent and by people on every level of cultural complexity, from hunters and gatherers to high civilization, including our own ancestors. Rather than being an exception, then, it has been the rule.
There is ample historical evidence to document the incredible propensity of parents to murder their children under an assortment of stressful situations. In nineteenth century England, for example, infanticide was so rampant throughout the country that a debate over how to correct the problem was carried out in both the lay and medical press. An editorial in the respected medical journal Lancet noted that "to the shame of civilization it must be avowed that not a State has yet advanced to the degree of progress under which child-murder may be said to be a very uncommon crime.
Infanticide has pervaded almost every society of mankind from the Golden Age of Greece to the splendor of the Persian Empire. While there are many diverse reasons for this wanton destruction, two of the most statistically important are poverty and population control. Since prehistoric times, the supply of food has been a constant check on human population growth. One way to control the lethal effects of starvation was to restrict the number of children allowed to survive to adulthood. Darwin believed that infanticide, "especially of female infants," was the most important restraint on the proliferation of early man.
While female infanticide has at times been necessary for survival of the community-at-large, there have also been instances where it has been related to the general societal prejudice against females which characterizes most male-dominated cultures.
Infanticide is not necessarily actively practiced - that is, the parents don't outright murder the baby, but rather cause it to die through selective neglect. This from "Health care allocation and selective neglect in rural Peru."
This study of health care allocation to children in northern Puno, Peru, utilizes quantitative and qualitative data to explore differential resource allocation to children in rural Andean households. As part of a broader ethnographic study of health in two communities, quantitative data on reported health status, symptoms, and treatments (both lay and specialist) were collected for 23 children under the age of 7 over a one year period. Additional data were collected from local health post records. Data were analyzed by gender, and by three age groups (birth to 1 year, 1-3 years, 4-6 years) to determine if differences existed in the allocation of health care. The data suggest a pattern of discrimination against females and younger children, especially infants under age one, despite the fact that these groups were reported to be sicker. Differences were especially significant in the allocation of biomedical treatments, the most costly in terms of parental time, effort, and money. Ethnographic data on child illness, gender, and developmental concepts help to explain why children of different genders and ages may be treated differently in the rural andes. They provide a context in which to interpret health care allocation data, and, in the absence of a population-based study, reinforce findings based on the limited study sample. Female children are valued less because of their future social and economic potential. Females are also regarded to be less vulnerable to illness than male children, meaning that less elaborate measures are necessary to protect their health. Young children are thought to have a loose body-soul connection, making them more vulnerable to illness, and are though to be less human than older individuals. The folk illnesses urana (fright) and larpa explain child deaths in culturally acceptable ways, and the types of funerals given to children of different ages indicate that the death of young children is not considered unusual. Health care allocation and ethnographic data suggest that selective neglect (passive infanticide) may be occurring in rural Peru, possibly as a means of regulating family size and sex ratio. It is important to go beyond placing blame on individual parents or on culture, however, to address the underlying causes of differential health care allocation, such as poor socioeconomic conditions, lack of access to contraceptives, and female subordination.
In spite of the fact that infanticide was widely practiced, it was still a difficult thing to do. Anthropologist Marvin Harris suggested that infanticide was so repugnant that until the invention of more humane forms of birth control, societies responded to times of abundant resources by allowing more children to live - eventually resulting in scarcer resources due to overpopulation.
While it must be difficult to kill any baby, it certainly must have been easier for parents to kill babies that refused to interact with them. Two of the three classic symptoms of autism are stunted social interactions.
According to the National Autism Association:
(Indicators of autism include):
1. Qualitative impairment in social interaction, as manifested by at least two of the following:
2. Qualitative impairments in communication as manifested by at least one of the following:
3. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole body movements)
Is it really a stretch to suggest that the reason that the ratio of male:female autism is so extreme is because female infants that displayed symptoms of autism were much more likely to be victims of infanticide?
It isn't just rates of autism though - baby girls are hardier in general than baby boys, and it seems likely to me that a plausible explanation is that baby girls have been selected for hardiness - the weaker ones died from selective parental neglect that was not practiced as much on baby boys.
And there ends the debate on nature vs. nuture - because if my theory is correct, it is cultural selection that resulted in a higher incidence of autism in boys, rather than some testosterone-autism connection that Baron-Cohen suggests.
Obviously this hyposthesis needs to be tested. But it's no more implausible-sounding to me than plate tectonics.