I'd like to thank you all for the insightful and philosophical discussion on the grave and serious matter of boobs.
IMO, we are left with three points to consider:
1) Are Dragonborn young hatched ready for solids, or do they require milk? ( Secreting from skin patches really doesn't work well with wearing clothing, let alone armour. Besides, breastfeeding is an iconic image of motherhood, whereas licking stuff off skin is kinda icky - and in a desert, sandy.)
2) What is the origin of the Dragonborn race? Are Dragonborn evolved reptiles, a variant draconic species, or transformed humans? The latter would entail vestigial traits that may not serve a practical purpose.
3) Which option is going to appeal to a larger segment of the market , and cause less arguments with artists and recalls of artwork?
I believe WoTC was mainly looking at 3.