This isn't a new trend, it's a long-standing custom in the South, especially among the older families.
Usually results when a girl of good family marries a guy of good family, and they want to preserve her family name in the line. No decent Southern girl would hyphenate her name (at least not until recently), so the parents would bestow her maiden name as a given name to her firstborn son.
This has happened over and over again in my family, and I'm afraid I did it to both my son and my daughter - although I did also give them a more "normal" name for convenience because my maiden name doesn't make as good a Christian name as some. This means that they have three names - which is considered odd unless you're an old-line Southerner (or a Catholic). But the bonus is that it makes genealogy a whole lot easier.
my plan was to name a daughter Mary Alexandra Kathleen (after 3 strong women in our family)F____________.
unfortunately, no female child.
free dixie,sw