Sally Mann, Art or Child Pornography?

So Sally Mann is a famous photographer known for her black & white photographs of her children, landscapes, and death. In some of her photos her three young children are often times nude, but not in suggestive positions. Her children grew up often times being in the nude as Sally Mann had. (I'm not going to post one of the photos in case someone takes offense, but you can easily find them on google if you search her name.) Would you consider this just another expression of art or child porn? 

*Her artwork was done in the late 80's-90's so her kids are now grown