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

Ya, it is normal. Babies breastfeed at this age and they know the bosom familiar to touch. I know it makes one embarrassed when baby does this, but I think other women too understand this. They know the baby is too small and since he knows the touch of breast, he does that. All you can do at this age is that when he is not breastfeeding do not let him touch your breasts, and if he does that, tell him 'no' and he will soon learn it. Also, do not be too harsh on him, he is just very little to get it fast.

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.