Single stack 9 if you want to stick with 9. I have seen some ballistic tests where penetration and expansion didnt differ much from .380 to .38. I did buy my wife a pink lcp, will be here tomorrow (thanks natgas for handling the transfer). My thought is, its better than the pepper spray thats in there now, more often than not, shes with me. You cant say that a bigger bullet is always better. I have heard of people getting shot in the head with a .380 and still walking around, and I have heard the same story about people getting shot with a .45. Shot placement is more important than anything. Just find something she likes, is comfortable carrying, and is capable of using. If she doesnt like shooting the .38, and wont carry it, it doesnt do any good. If she likes shooting it, but doesnt like carrying it, it does no good. So sometimes there are compromises that have to be made (capacity, caliber etc) but ultimately, a .380 is better than the alternative, which is nothing.