Last week, I wrote a column about attending a playgroup for same-sex parents. The column earned some feedback on the Daily Journal’s Web site. Some good. Some bad.

I find the whole concept of gay and lesbian families very interesting. There hasn’t been much written about these non-traditional families until recently. One of the most recent studies comes from the “Journal of Economic Perspectives.” Professor Dan A. Black of the University of Chicago along with Seth Sanders of the University of Maryland and Lowell Taylor of Carnegie Mellon University published their paper titled, “The Economics of Lesbian and Gay Families” in the Journal’s spring edition.

Using data from the 2000 census, Black and the gang concluded “that gays and lesbians are not innately different from heterosexuals, but that biological and social constraints affect many of their decisions.” This particularly holds true when it comes to raising a family.

Some of the highlights of the paper include:

* Gays and lesbians have fewer children than heterosexual couples. Only 38 percent of heterosexual couples do not have children, while 77.9 percent of lesbian couples and 90.3 percent of gay male couples have no children. Biology is the main factor for the discrepancy. However, the authors also site discrimination towards same-sex couples as an added barrier to large families. Such discrimination is often seen through increased fees for same-sex couples interested in adoption and more red tape issues.

* Lesbian couples are more likely than gay male couples to have children. As a result, lesbians are less likely to settle in expensive urban areas.

* Gay male couples are often located in upscale cities. In fact, there are more gay male couples than heterosexual couples living in several posh cities including San Francisco, Austin, Los Angeles, New York and Seattle. Black and his co-authors argue that because gay male couples do not tend to have children, they have more disposable income. This extra income is often spent living in high-amenity, urban areas.

* Gay and lesbian couples with children are more likely to have a stay-at-home partner. Similar to heterosexual couples, the partner who stays home in a same-sex relationship usually has fewer years of formal education.

It’s amazing what you can learn by looking into people’s wallets. I guess economics really is a social science.