While I think every girl should be able to wear what she wants without fear of criticism (your body, your choice!) I do worry about what impression wearing one would give off. No, I'm not talking about how others will judge their bodies...I'm worried about the message the actual bikini is sending to them!
Our culture is shaped by dominant ideology about what is okay to wear, what is feminine, what is masculine...etc. What message are we sending to young girls? That they need to be sexy! Sexy = Landing a Man....and we are learning and teaching this so young! The sexualization of girls only reinforces the idea that women's bodies equal their worth and this should not be the message we are sending.
When talking to your daughter about bathing suits, if you are not allowing her to wear a bikini quite yet, make sure you tell her that it is not about what her body looks like or how revealing the suit may be. It' such a slippery slope because all girls should be allowed to wear what they want and wear what makes them feel good, however we have to remember WHY girls think these things make them feel and look good. As an adult, you have the ability to understand all of these factors but as a child you may not.
My advice is to not ever make a child feel shameful for either wearing or wanting to wear a bikini! Sometimes a simple compromise on bathing suit style and talking to her about making these decisions when she is older may help! Help your daughter love her body in any bathing suit style by focusing on teaching her about why her body is actually important (to walk, play, grow)...
I guess you could say is my problem is not with girls wearing bikini's...it's with the fact that they play a part in socializing them and setting them up for future body dissatisfaction and sexualization! What do you think?