My brother and sister in law first picked the initial name (AJ).
Then found out the sex (girl).
Then picked the name.
I think picking a full name based on what you want the nn to be a bit silly.
And, overall I find initial names to be “sporty” sounding to me.
Buuuut whatever floats yer boat! There are certainly more egregious way to name a child.
I don’t care for it personally but with few exceptions. Being [name]Kristina[/name] [name]Kaitlin[/name] I have picked up the nickname K.K., over the years. I think it flows well (maybe because I’m used to hearing it) but I don’t care for the more comman initials as in J.J., J.R., or K.C. I do like certain ones like M.G., G.T., T.L. though.
I know a MB ([name]Mary[/name]-[name]Beth[/name]) and a MK (I don’t even know). I’m not a fan of them, mostly, but there are a few exceptions as always. In the movie [name]Juno[/name] [name]Juno[/name]'s little half-sister was named [name]Liberty[/name] [name]Bell[/name] called LB, and I assumed it was Elbie at first which I though was a pretty cute nn from something completely different. I think a lot of the L ones have that same theme which I like. Normally I’m really not a fan, though.
I know more than one [name]James[/name] called by his first and last or first and middle initial… a J.P. , J.D. and J.T.
I’ve never actually seen this trend with anything except the name [name]James[/name], maybe because it’s so popular? I’m not so sure, but I think it can be cute on a boy, but on a girl it just seems a bit odd.
*Correction: My brother has a friend named John J-last-name Junior, called J.J. and occasionally even J.J.J.
Still, the J’s seem to be a thing.
I would never give a child a set of initials I didn’t find appealing together, and felt was usable as a name. I have been known to try to come up with names to match attractive sets of initials.
I probably wouldn’t call a kid by their initials to the exclusion of all else as their primary nickname. But I don’t see it as tackier than any other nickname and less than some. Find it much less annoying than some of the very convoluted justifications for nicknames you see on Nameberry sometimes involving instructions like “take the first syllable and last syllable off and change all the vowels and squint slightly and suddenly you can see it! Oh well, we’ll just tell people to call her that.”
I have known a T.J. who was a girl, and many C.C.s who were girls (and I find C.C./Cece cute whether its short for [name]Cecilia[/name] or initials). For boys I have known many X.-somethings who were Xaviers and Z-somethings who were, I suspect, Zacharys. And the J-names.
My dad calls me J.G. but nobody else does. A number of people in the family call my brother A.W.
That’s an interesting point. My initials are O.C.D. , and while that’s unusable in general for obvious reasons, they’re just kinda… ugly.
I’m definitely not a fan of them. It’s just too easy for them to come off as either lazy, tacky, or just trying way too hard to sound “peppy happy quirky”.
[name]Bingo[/name]! lol. Not really a fan of initial names, it seems a waste, but I really have come to love JJ because of CM. (And she’s not exclusively JJ all the time; when she introduces herself to people she tells them her name is [name]Jennifer[/name].) I tried to talk my roomies into giving their son a J middle name to go with his first name ([name]John[/name]) so they could use it, but no luck, lol.
[name]Alexis[/name]
I’ve always thought that they were only used when someone didn’t like their name. For example, I knew a CC that really didn’t like her first name, [name]Cornella[/name], so she was always known as CC (The second C represented her MN, [name]Catherine[/name]).
Anyways, here are some combinations I’d use with the initials you provided:
J.J- Boy: [name]Joshua[/name] [name]James[/name], Girl: [name]Julia[/name] [name]Jane[/name]
C.J.- Boy: [name]Charles[/name] [name]Joseph[/name], Girl: [name]Claire[/name] [name]Josephine[/name]
K.C.- Boy: [name]Kieran[/name] [name]Casey[/name], Girl: [name]Kasia[/name] [name]Claire[/name]
K.T.- Boy: [name]Kevin[/name] [name]Thomas[/name], Girl: [name]Katherine[/name] [name]Therese[/name]
M.J.- Boy: [name]Marcus[/name] [name]Jacob[/name], Girl: [name]Melisande[/name] [name]Juliet[/name]
M.K- Boy: [name]Marcello[/name] [name]Kai[/name], Girl: [name]Marie[/name] [name]Kathleen[/name]
Good luck 
I think that initial names are a great nickname option, especially if a child isn’t fond of their given name. My name is [name]Mary[/name] [name]Jean[/name], and I’ve never felt like a [name]Mary[/name], or a [name]Jean[/name], so I’ve pretty much have always gone by MJ, which I like a little bit better. But personally, I have found it kind of annoying through life, explaining my full name, asking people to call me MJ instead, etc. Also, I’ve always wanted to find a more original nickname, but you can’t get much more nick-namey than MJ : /
As other people have pointed out, going by your initials can add a distinguished flair to your name. I agree, but I’ll admit for most of my life I never really got it. It’s still not really my style, and I would only do it for some symbolic nod to something or another (naming after a family member, for example).
My brother was called J.P. throughout most of his childhood (for various reasons, but my mom also liked the dignified ring it got from the association with J.P. [name]Morgan[/name]). He ended up hating that, though, because inevitably people would ask him what his initials stood for and he was ashamed of his middle name because he thought it was weird ([name]Perry[/name]-- I love it, actually). So now he goes by his first name in public.
I also know a T.C. (male). In this instance, I don’t like it, because I don’t think TEE SEE sounds good. Maybe for a girl, I’d like it more. I mean, it’s not HORRIBLE, but not my taste.
Agreed. I’ve never come across one that I’ve liked - it always seems as if the parents picked the initials first and tried to match names together, or gave their child a name, but ruined its beauty by calling them by their initials.
Another one I’ve come across is M.T., and while I love the girl, her name sounds like “empty.”
Also, how do people who go by their initials sign their names? A.J. or C.J just doesn’t seem complete and/or formal enough to me.