Well when I looked at the website the sculptures there look like ancient art to me. In a Modern Art museum the sculptures would be more graphic I would say.
Is all their artwork posted on their site? I just saw a photo of the nude sculpture from the "Sensation" exhibit a few years ago - women with penises for noses and anuses for mouths. I'd be very upset about a kid being told that was Art (more so than I would be about him seeing it). I just think there's got to be more to this than standard nude sculptures.