There are FAR WORSE initials ur child could have. Just as an example...here are some of my co-workers initials (i work in a hospital inpatient pharmacy and we have to initial everything we make, fill out, or deliver...)
BV (bacterial vaginosis)
BM (bowel movement)
BS (bullsh*t)
TB (tuberculosis)
DD (its a girl with a large chest...so u can imagine lol)
KKK (no lie...her birth name was Kayla Kristine Mathers...then she married a man with the last name King....)
ASS (another girl who married into her initials lol)
STD (his parents didnt think first lol)
So believe me it could be worse.
Also, My last name starts with V...so I have to be careful with medical viruses. For instance...when I pregnant with my first, the girls name I picked were...
Hailey Isabel, Hailey Paige, Brianna Lee
INITIALS.... HIV....HPV....BLV (not too bad...but without the middle name...its just BV)
MS is innocent. I mean change it if ur that worried, but I work with 2 MS's and we dont give them hell for it at all lol.