Applied to the genitals it does help to increase your levels, but they also drop faster. So a higher spike but deeper trough before you apply the next lot. I can't speak on increased risks but my endo hasn't said anything against applying there.

Application to the chest does increase breast tissue density, which in turn increases the risk of breast cancers so its definitely not worth it considering increased density does not equal increased size, just increased risk.

Application to the lower abdomen and thighs is the recommended method and leads to the most stable levels and least risk overall. That said i personally get good results applying to the inner thighs and genital area, about 40 percent on each inner thigh and the remaining on the genital and above area.