The Number One girls’ name of the decade so far is Emily, with about 190,000 babies receiving that name since 2000.  And the top boys’ name is Jacob, given to nearly 229,000 boys this decade.

　　But there are other names that are given to more than twice as many babies as those Number One names.  Not many parents realize that the names they’re choosing carry this huge degree of popularity.  No states or government agencies track these names or alert people to what vast numbers of children receive them.

　　Why not?  Because they’re not a single name but a meganame, or a cluster of names, if you like.  These are names that are closely related in form and spelling, with lots of overlaps that sound exactly alike.  There are many examples in modern U.S. baby names – including to some extent Jacob and Emily themselves – but let’s focus on three of the most notorious.

　　For boys, the premier meganame might be thought of as the Aden cluster.  It includes the following names, arranged so that the relationships are most obvious:

　　ADEN

　　AIDEN

　　AIDAN

　　AYDEN

　　BRAYDEN

　　BRADEN

　　BRADY

　　CADE

　　CADEN

　　CAIDEN

　　CAYDEN

　　KADEN

　　KAIDEN

　　KAYDEN

　　HAYDEN

　　JAYDEN

　　JADEN

　　JAIDEN

　　JAYLEN

　　JALEN

　　There are undoubtedly more variations and spellings that might be included here – we didn’t diverge to Adrian or Zayden, for example – but taken together these names were given to about 480,000 baby boys in the 2000s, more than twice as many as received the name Jacob.

　　Of course, Brady and Jaylen feel fairly different – but Aden, Braden, and Jaden don’t, and Caden, Kaden and bros sound exactly alike.  Unsuspecting parents, especially those who haven’t been around kids much since they moved up to middle school themselves, might hear a name like Hayden or Aiden and think, wow, that’s really unique.  I want a special, modern, stand-out name for my son, not something everybody uses, like Jacob or Michael or Matthew.

　　And then they end up with a name that’s twice as common as any of those popular individual names.

　　For girls, let’s look at the meganame we might call Aylee (or Ayla or Kyla).  It’s far-ranging, and while you might not agree that every name below should be included in the cluster, there are many we left out.  This name cluster embraces:

　　BAILEY

　　BAYLEE

　　HAYLEE

　　HALEY

　　HAILEY

　　CALLIE

　　KAILEY

　　KAYLEE

　　KAYLEIGH

　　KAELYN

　　KAYLA

　　JAYLA

　　SHAYLA

　　MAKAYLA

　　MIKAYLA

　　KYLA

　　SKYLA

　　SKYLAR

　　SKYLER

　　KYLIE

　　KYLEE

　　RYLEE

　　RYLEIGH

　　Nearly 540,000 girls received these names this decade, compared with fewer than 200,000 who were named Emily.  And again, there are many more variations that might be lumped in with this group.

　　Another megapopular name that crosses gender lines is the Alex cluster, which accounts for nearly half a million baby boys and girls born this decade.  The names we’ve tallied in this cluster are:

　　ALEXANDRA

　　ALEXANDER

　　ALEX (boys)ALEXA

　　ALEXIA

　　ALEXIS (both genders)ALEXUS (girls)LEXI

　　LEXIE

　　ALESSANDRA

　　ALEJANDRA

　　ALEXANDRIA

　　ALEJANDRO

　　ALEXANDRO

　　ALEXZANDER

　　The lesson: Alex might be a solid, attractive name that works equally well for boys and girls.  What it’s not is distinctive.

　　If you end up deciding you love Hayden or Hayley or Alexa anyway, go right ahead and choose them.   Just be aware that any name that’s got lots of close relatives is bound to feel far trendier than you’d guess by gauging the popularity of that name alone.

　　Thanks to our wonderful intern Danielle Miksza for her help with the research and math for this post.