Is it possible to have attached earlobes if both of your parents have unattached earlobes?

Yes it is your possibility if the parents were both heterozygous(having different alleles) or hybrid with Aa and Aa, the genotypic ratio would be 1:2:1 so if you put it in a punnet square there is a 25% chance of AA, 50% chance of Aa and 25% chance of aa.