Whenever my baby boy (1.5yo) meets another lady, he tries to touch her breasts! Is this normal or should I be worried?

If you're breastfeeding your child, it's quite normal but yes, this can be embarrassing. You should begin enforcing your kid to not touch your breasts when not feeding her and also tell him in clear words that he should not touch other females' breasts. Will take some time, but he'll learn.