I’ve seen it done in a very cute, more subtle way (a family I know has three daughters: [name_f]Catherine[/name_f], [name_f]Cordelia[/name_f], and [name_u]Chelsea[/name_u]) and I’ve seen it done in a more obnoxious way (i.e the Duggars).
I am torn between liking it for the continuity and connection between all the siblings, and disliking it for the uniformity and matchy-matchy feeling it gives.
What do you think? Would you name all of your children with one letter? Boys AND girls?
I think if its done subtle its okay and doesn’t bother me. I think 3 children though is the limit. After you try to match names for 3+ children it feels like your trying to hard. I think it also depends on the names, I know someone with 3 boys named [name_m]Jeremiah[/name_m], [name_m]John[/name_m] [name_u]Michael[/name_u] and [name_m]Jacob[/name_m] and I think that’s subtle and nicely done, I also know brothers [name_m]Jason[/name_m] and [name_m]Jaidon[/name_m], and I think that’s too close for me personally.
If it’s done nicely, I have never come across such sibling sets in real life but will not be a problem as long as each name has its own character.
I don’t like matchiness among sibling sets, but some letters it is creative to make it asthetically pleasing but also avoiding matching sounds.
Examples:
[name_u]August[/name_u], [name_f]Abigail[/name_f], and [name_u]Asa[/name_u], (short o sound, short a sound, and long vowel sounds)
[name_m]Cyrus[/name_m], [name_u]Channing[/name_u], and [name_f]Coralie[/name_f]
[name_m]Emrys[/name_m], [name_m]Eli[/name_m], and [name_m]Eamon[/name_m]
Or maybe something like [name_u]Quincy[/name_u], [name_f]Coralie[/name_f], and [name_f]Kaia[/name_f], but I dislike matching sounds
I think it’s fine and actually enjoy it if it isn’t overdone/too matchy (e.g. [name_f]Lily[/name_f] and [name_f]Luna[/name_f] is fine to me, but [name_f]Luna[/name_f] and [name_f]Lucy[/name_f] is too much). My aunt is actually one of nine kids and their names all begin with one letter and are very separate from each other (think [name_f]Elizabeth[/name_f], [name_f]Emily[/name_f], [name_m]Evander[/name_m], [name_m]Elijah[/name_m], etc.).
I like it and I’ve toyed with the idea, as long as they aren’t too close then I think it’s a sweet connection (e.g. [name_f]Claire[/name_f] and [name_f]Cordelia[/name_f] vs. [name_f]Claire[/name_f] and [name_f]Clara[/name_f]). I like the idea of boys with one letter and girls with the other, or them all the same, but I don’t love enough names all beginning with the same letter to consider it.
A while back we’ve been on holiday with a family whose two daughters’ names are both relatively short and begin with the same letter and between all of us their names have been mixed up a lot.
While I think [name_f]Alice[/name_f], [name_f]Ada[/name_f] & [name_f]Amelia[/name_f] work nicely together as they’re relatively different in sound, something like [name_f]Clara[/name_f] & [name_f]Cordelia[/name_f] would be too similar for me.
It’s fine as long as the names are not too similar, for example, [name_f]Samantha[/name_f] and [name_m]Samuel[/name_m]. [name_m]How[/name_m] ever I always thought it would be cute to sisters named [name_f]Sylvie[/name_f] and [name_f]Stella[/name_f].
I pretty much agree with previous posters, that it can range from terrible to totally fine depending on the names themselves and how matchy they are in other aspects.
The only thing I really dislike about it is the way it limits options for future kids once you’re locked into a pattern. If you like 4 J- names and have 5 kids, then kid #5 ends up stuck with either a name their parents don’t like, or being the odd one out. Best case scenario they get an irritating misspelling of a name their parents like and would ordinarily have been content to spell the easy/correct way.
tl;dr It can work, but I wouldn’t do it unless you have tons of distinct favorite names with that initial (for all genders)
That’s what my parents did for their children, and it was a bad idea. Since we all have the same initials, there has been a lot of confusion, and I’m often called my sister’s name or vice versa.
I think “subtle” is hard to do; if they start with the same letter… they start with the same letter. S or C you can get away with if you go SH or CH - Catherine, Chelsea, and Celeste is more subtle because of the differing sounds, for example, than Catherine, Cordelia, and Chelsea. It’s also more obvious the more kids you have and/or the closer they are in age, or if you start changing the spelling to match your chosen letter - Jinger comes to mind.
I wouldn’t do it myself; in fact, I try not to duplicate initials. I’m pregnant with number 11, and I’m down to focusing on about half the alphabet. 
I feel the matchy-matchy uniformity kind of overshadows any feelings of continuity. I feel like it’s a sort of ham-fisted way to go about achieving meaningful names for kids. I also feel like, as much creativity as you need to come up with yet another M name, you’re actually blocking yourself off from so many good, creative, beautiful, meaningful choices by locking in on an initial (or a one-and-only style, for that matter).
My ex-[name_f]MIL[/name_f] named all four kids w/names that begin w/the same initial as their last name: [name_m]Roger[/name_m], [name_m]Rodney[/name_m], [name_f]Rhonda[/name_f], & Raeshel. My ex suggested using a girl’s name that began w/R, but the only two I liked he didn’t, so that idea got dropped pretty quickly. My ex-[name_m]BIL[/name_m] & his ex named their kids w/names that began w/an A, a B, & a Z. One ex-[name_m]SIL[/name_m] used names for her son & daughter that began w/the same letter, but it wasn’t the same letter as the first of their last name, & the names sound distinctly different from each other.
In my own family, my dad was named after one of his maternal uncles. Coincidentally his first name began w/the same letter of his father’s first name. My grandfather went by a nickname that’s not usual w/his name, but is identical to the standard nickname to my dad’s name. While my dad was growing up they had “Big [name_u]Jerry[/name_u]” & “[name_m]Little[/name_m] [name_u]Jerry[/name_u],” but then [name_m]Little[/name_m] [name_u]Jerry[/name_u] got bigger than Big [name_u]Jerry[/name_u], so they became Old [name_u]Jerry[/name_u] & [name_m]Young[/name_m] [name_u]Jerry[/name_u]. As you can imagine that didn’t last long, so then there was just confusion over which [name_u]Jerry[/name_u]. And my own nickname rhymes w/[name_u]Jerry[/name_u], just to add to the confusion.
I agree that it really does depend on the set, but more often than not, I don’t like the similarity. I’m fine with it if it’s only one or two out of a larger set, and especially if the sounds are different (e.g. [name_f]Catherine[/name_f] and [name_f]Cecilia[/name_f]). But generally I overthink stuff like this. I’d feel obliged to continue using the same first letter even after 2 kids, so no one is left out, but I also think that comes across as repetitive and uninspired. I struggle to use names with the same ending (apart from -a), so I’m definitely not a fan of similar beginnings.
Personally I wouldn’t. My father and brother shared a first initial and after the breakdown of my parent’s marriage, my brother always found it difficult to be referred to as Mr M <last name>.
However, I don’t think it’s inherently wrong for children to have the same first initial as long as their names are separate enough for them to have their own identity.