For some it's a deliberate act - choosing names for their babies that start with the same letter, like the Duggar family who have 19 children all with names starting with the letter J.
The Kardashian Jenners have also banked successfully on their kids' alliterative names to deliver an air of glamour to their family business, with the five sisters all bearing K names.
For others, it's simply a coincidence that a prospective name for a new baby happens to begin with the same letter as an older sibling or two.
But what do people in the real world really think of the practice?
It's a topic that's come up in the name forums at Mumsnet, a treasure trove of baby name discussions that can give us an insight into the complex, fraught and often political baby naming landscape of English-speaking societies.
A second-time parent-to-be has started a thread in which they say they never anticipated liking such a name, and is asking for advice about whether it's a bit tasteless or not.
"I always said I wouldn't but absolutely adore a name that starts with the same letter as DC1 (Dear Child 1)? Thoughts?" also adding a question about whether it's tacky or not.
The key seems to lie with whether there ends up being more than two siblings. Many agree there's an written rule which states that two beginning with the same letter is fine, but any more than that and you're heading into public judgement territory.
"I don't see it as chavvy [tacky] at all (unless you have 26 children who all begin with the same letter, and take liberties with spellings to make all the names fit the pattern), but I wouldn't do it myself for practical reasons - letters being opened by the wrong person," replies one person.
Another writes, "I think 2 siblings with the same initial is fine but more than that is a bit naff. I know a woman with 4 kids all beginning with C... It's a bit corny in my opinion."
This commenter has two children whose names start with the same letter, but agrees it's not on for a third baby.
"My two do , they were the names we liked. I am fine with it but won't do the same with a third, that's too much for me!"
Some astutely say it depends on the actual names.
"Depends on the names. Theodore and Tamsin would be fine but Lulu and Luca sounds stupid..."
"I don't think it gets weird until the endings are matchy too. Nothing wrong with Aaron and Amelia or Toby and Tristan, but Tilly, Tommy & Toby is a bit naff."
Others think it wise to steer clear of letters like K and J in case they look as though they're trying to be the next Duggars or Kardashian Jenners.
There's the usual mentions of mail mix-ups between siblings with some believing that the sex of the children plays a part in the inconvenience.
"If the children are of different sexes, then I'd say go for it. If they are both the same sex, you may have problems when they are older and get post. E.g. Which Mr R Meadow is this for?"
This commenter backs up this assertion.
"Never bothered me and my brother though we did often open each others post by mistake."
We're all going to have an opinion about matching sibling intials, with some who would be bothered by it, and others who think it's desirable.
Whether it's tacky or not depends entirely on the beholder, and parents should really just name their babies as they wish.