By coincidence two (female) members of my family have said this within a week of each other.
One about a photo I sent of my 2.4 DS in some sunglasses - she replied with a text saying "looking sexy!" and then I sent a photo of my 4mo old DD in an outfit that an Aunt had bought her, saying thank you for the outfit and the Auntie in question replied "wow, sexy even at 4 months"
It makes me uncomfortable...