With Australia currently engaged in an abysmal debate over same sex marriage, it‘s refreshing to be reminded that morality often has a utilitarian history.

For example, this recent paper suggests that norms around illegitimate children are based in economics.

Based on data from the Austro-Hungarian Empire and modern Austria,
we show that regions that focused on animal husbandry (as compared to crop farming) had significantly higher illegitimacy ratios in the past, and female descendants of these societies are still more likely to approve illegitimacy and give birth outside of marriage today.

The key point is actually buried a fair bit down in the paper. The reason there is this split in social norms between crop and animal farming communities is apparently due to differing labor structures.

18th and 19th century workers on crop farms were on short term contracts, often working as day labourers.

In crop farming, the work load and the resulting demand for additional
labor, is determined by the rhythm of the seasons… additional manpower is needed in the harvest season.

Workers on animal farms, meanwhile, had long term contracts. This was less precarious, but they also tended to live on the farms and so had little opportunity to create their own households. Their illegitimate children were tolerated by the communities.

In contrast, in animal husbandry the workload is distributed relatively evenly throughout the year… Animal husbandry requires a sound knowledge of the peculiarities of each animal (analogous to firm-specific human capital), while harvesting is less specific.