>>11794617>Note, however, that these administrative data do not include a direct measure of sexual orientation. We define same-sex parents based on detailed household information from the Dutch population registers. As a result, we solely study couples, because we cannot determine whether a single-parent identifies as gay.Good grief.
Here, I hope this one isn't an "obscure press article" to you.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771005/#__ffn_sectitle 