I think you two are missing the point of the article which is that society's dismissal of God's sexual ethic of "absolute monogamy" between men and women results in negative societal (and civilization) consequences that include the devaluation of marriage as an institution amongst most members of society and subsequently a participation rate decline amongst a population who no longer hold it sacred followed by a declining birth rate.
Statistically, consequential evidence of same-sex "marriage" is already manifesting in a birthrate reduction. For example, in 2007, a correlation between low birth rates and the legalization of same-sex "marriage" in five U.S. states that granted marriage licenses to same-sex couples reveals that four of those five states ranked within the bottom eight out of all fifty states in both birth rate (measured in relation to the total population) and fertility rate (measured in relation to the population of women of childbearing age).
Twelve of the sixteen states granting benefits to same-sex couples rank in the bottom twenty states for birth rate, while eleven of them rank in the bottom seventeen in fertility rate. In fact, Vermont, the first state in the U. S. to offer 100% of the rights and benefits of marriage to same-sex couples through passage of its "civil unions" law, ranks dead last in both birth rate and fertility rate. See: "Births: Final Data for 2007," National Vital Statistics Reports Vol. 58, No. 24, August, 2010, Table 11.
The same pattern is seen internationally for nations that permit same-sex "marriage." See: "Country Comparison: Birth Rate," The World Factbook (Central Intelligence Agency).
It's true that many factors can play into a rise or decline of a nation's birthrate (e.g. food production, mortality, patterns of birth control usage, etc...); however, the present devaluation and decline of marriage between men and women certainly stands out as a primary driver for the latter (and I would argue especially when the ability of government to artificially maintain out of marriage procreation is finally curtailed due to escalating interest expenses on the rapidly rising debt).
The available statistics support the assertions made in the article which offers sound scholarly reasons why:
http://www.thepublicdiscourse.com/2015/04/14885/