This whole idea that people with biological children are more invested in the future of the country than those without kids is just a thinly disguised dog whistle that’s firmly rooted in misogyny and homophobia.
This is a line that theoretically doesn’t precisely and specifically just target homosexuals, there’s also “collateral damage” to infertile couples and those who choose to go child-free. And there’s a sufficient number of those people that it serves as the basis for plausible deniability. That they specifically call out “cat ladies” fully reflects the misogynistic aspects of it. But make no mistake, this is undeniably a basis they might use to deny rights to the LGBT+ community.