| I maintain a datamatching application that monitors the accuracy of government social security payments. For certain routines it checks payments made to couples, parents and widows, using business rules based on a legislative regime that assumes legitimate partnerships necessarily involve two people of different sex.
In recognising same sex relationships as having the same rights as heterosexual relationships, organisations may need to tinker with their bedrock metadata to make their systems able to process such couples.
In my case, by assuming that a couple will be heterosexual makes life easier for programming. Just move the blokes into table A and the ladies into table B, carry out an inner left join between both tables and check the results (usually it is more complicated, as we have historical data to check). I would guess that in several other computer applications around the world that stores and processes the relationship details of people (such as insurance policies, joint bank accounts or pensions), the original coders were happy to organise these variables in absolute terms (x = male partner, y = female partner), rather than relative terms ( x{y}spouse = y{x}spouse).
Without having gender to deliniate each member of a same sex relationship, the basic metadata structure of entire databases might need to be adjusted. This could lead to more IT work becoming available, in the manner that Y2K and the European Monetary Union prompted spikes in demand albeit thanks to some hype, due to a seemingly trivial change to a data field's attributes.
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