“I simply don’t believe this is true from a familial standpoint.”
I took it to mean “extended” family. IE: cousins, aunts, uncles, children grandchildren, and so on. Extended family usually can contain a surprisingly large number when you sit down and add them up.
I don’t think the author meant “immediate family”.
I know of NO ONE in my extended family that is gay. I simply don’t believe it....3.5% (if you concede that number is true) doesn’t even account for the claim.