Mary-Kate and Ashley. Kate and Rooney. Kim and Khloe (and Kourtney… and Kendall… and Kylie.) There aren’t any steadfast rules for naming siblings. It all comes down to personal preference. Sticking with the same first letter is a choice that some families clearly prefer (hello, Kardashians) while other parents stick with the last letter, instead (think Maddox, Pax, and Knox). Still, parents who are figuring out how to name siblings may want to look to some simple guidelines.

You’re envisioning brothers and sisters who get along, right? So you’ll want to give them a harmonious start in life with names that are complementary. And that goes deeper than monikers that sound compatible. Think about the theme of your name. Some names mean fire, like Aiden or Emma. Others are synonymous with water, such as Marin or Dylan. Fire and water are two elements you may want to consider when naming siblings. When picturing potential future squabbles, rivalry, and competitiveness, might you want to pick similar themes to just to be on the safe side? Here are 11 other ideas to consider (and possibly avoid) when naming siblings.

1. Matching Initials

Giving siblings the same initials is a sweet way to kickstart their connection. On the other hand, it may hinder the labeling of clothes, lunchboxes, and other belongings. Just saying.

2. Similar Origin

As with any of your name choices, this isn’t a hard and fast rule, but sibling names from the same origins can be connected and consistent without being too similar.

3. Cities

London and Paris are popular names for twins, and city-inspired names are a great idea – especially if they hold some significance to you and your SO (for example, you lived there together or your babies were conceived there). But if you plan on adding to your brood, make sure you have plenty of pleasant-sounding monikers to choose from.

4. Names That Follow A Theme

Certainly, Lily and Daisy are lovely names, but if you’re planning on a large brood, you may want to steer clear of a group of names that are so similar and potentially limiting. These are your kids, not the flower selection at the local farmer’s market

5. Famous Pairings

No question about it, William and Katharine are two solid names. Just keep in mind that their short versions are Will and Kate – and while the Duke and Duchess of Cambridge are beloved by many, that doesn’t mean it’s a good idea to name a brother-sister duo after them. Do you really want sibling names that are so well established by other people? (Not to mention, people who are married to each other.)

6. Movie References

When you’ve come up with any name, do your child a favor and Google it first. A lot of famous movies have a name for a title. And no matter how old the film is, it’s a medium that lives forever. The Audrey Hepburn classic Sabrina? Lovely. But choose a name like Emily Rose or siblings named Emily and Rose (as in The Exorcism of…) at your own risk – and to the delight of movie nerds everywhere.

7. Nicknames

Think about nicknames at the same time you’re picking out names. Nameberry points out the unlikely – but possible – scenario of three siblings named Rory, Joseph, and Owen (nicknames: Ro, Joe, and O). Of course, rhyming nicknames may be exactly what you’re going for; it’s just something you’ll want to consider ahead of time.

8. Gimmicks

Heaven and Nevaeh (the same name, then spelled backward) are honest-to-goodness twin girl names. And although nothing’s wrong with either name, the concept is kind of gimmicky.

9. Famous Rivalries

Rivalries have been around for years, and naming your children after famous nemeses won’t necessarily create an everlasting bond. Still, you may want to avoid giving them opposing names, like Sunshine and Storm, or Rose and Thorn.

10. Sibling’s Choice

Asking your firstborn to name the bundle-of-joy-on-the-way is a loving gesture of inclusion, but can totally backfire if your little one has mixed feelings about the new addition. Of course, you’ll say no to “Doody Head” as a name, but then, why did you ask in the first place?

11. Names That Don’t Match At All

Even if you want each family member to be named with individuality in mind, names that are too different can bring discord to mind. Jane and Jupiter are a good example of names that clash, even though they start with the same letter. On the other hand, you’re choosing your children’s names with all the love in the world. Mismatching names won’t really be a harbinger of rivalry – seriously, name your kids what you want!

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