It is just a myth. Rice will not raise estrogen levels.
White rice scores very high on the glycemic index. White rice has a GI rating of about 70, and brown rice has a slightly lower rating of 55. Brown rice is a much better choice then white rice.
To make white rice, they remove the bran and germ of the rice grain. That is where all the fibre and minerals are. White rice is fine for the occasional cheat meal but you should base your diet on brown rice.