A: Yes. Hybrid soak-off gels (e.g. Shellac, Gelish, Axxium) are less damaging than the old style long-lasting treatments which needed to be filed off for removal (often taking a chunk of your natural nail with it), but a recent study found that they still caused significant weakness, thinning and brittleness. In one measurement, the nail was measured to be about 50% thinner!
Whether it's the chemicals in the polish, or the application/removal process that damages the nail is unknown. This is something to be aware of, since gel polishes are often seen as good for nails. Thin-nailed girls - be careful! One option that seems to be getting good reviews though, is Bio Sculpture gel.
A F Chen, S M Chimento, S Hu, M Sanchez, M Zaiac and A Tosti. Nail damage from gel polish manicure. J Cosmet Dermatol 2012, 11, 27.