Pressure sensitive adhesive compositions having enhanced resistance to water-whitening comprising an aqueous emulsion polymer are disclosed. The polymer comprises the polymerization reaction product of a polymerizable aqueous emulsion comprising: (i) at least one hydrophobic alkyl acrylate or alkyl methacrylate ester of an alcohol, (ii) at least about 1 wt. % of at least one hydrophilic monomer, (iii) at least about 5 wt. % of at least one partially hydrophilic alkyl acrylate or alkyl methacrylate ester of an alcohol, and (iv) a water-soluble or water-dispersible polymerizable surfactant selected from compounds having a terminal allyl amine moiety, substituted phenyl compounds having at least one alkenyl substituent, polyoxyalkylene-1-(allyloxymethyl) alkyl ether sulfate salts, or mixtures thereof, and the average particle size of the polymer is less than or equal to 200 nm. Also disclosed are processes for preparing same.