No, I don't think so, if it was harmful, mothers with infants would have harmed breasts ;)
YES
nope. sucking to normal girl breast is not harmful
Can sucking in your stomach while pregnant be harmful?
Breast sucking will not avoid breast cancer.
maybe
No it is not.
they get smaller :)
It's not harmful assuming none of the people have STDs.
Yes
When you start sucking on it.
Sucking on a wife's breast can help enhance emotional connection, increase pleasure during intimacy, and promote bonding between partners.
stop!
No it does not.