They can kiss, just as anyone else can but whether you're talking of a kiss on the cheek or a kiss kiss is a different matter. Technically speaking, of course they can, but it's considered incest if it's a kiss kiss which is illegal in some places. They can still do it though.
Brothers and Sisters - 2006 A Righteous Kiss 5-4 is rated/received certificates of: Netherlands:6
He had 11 brothers and sisters.
There are 4 brothers and 3 sister's all up. Assume your one of the brothers - hence you have 3 brothers and 3 sisters. However any one of your sisters, would have 4 brothers and 2 sisters.
no she has no brothers or sisters.
yes, 7 brothers and sisters
he had 2 brothers and 3 sisters
She had 12 brothers and sisters
Athena had no brothers or sisters.
not have any sisters or brothers
brothers and sisters
The Sisters Brothers was created in 2011.
Black beard had no sisters or brothers