D
Any hint of wave is considered wavy/curly. In order for hair to be considered straight, it has to be board straight with no wave at all. This web page from Stanford University explains it better than I can: Understanding Genetics
Basically, CC is curly, ss is straight, Cs would be wavy. In order for someone to have straight hair, they'd have to inherit two recessive straight genes from both parents. If your Dad had wavy hair, then is genotype would be Cs, but his phenotype would be wavy. He could give you the straight hair gene, along with your Mom. This means that two people with wavy hair could have children with straight hair, since the wavy genotype is Cs.
I hope I did not thoroughly confuse you,
Basically, CC is curly, ss is straight, Cs would be wavy. In order for someone to have straight hair, they'd have to inherit two recessive straight genes from both parents. If your Dad had wavy hair, then is genotype would be Cs, but his phenotype would be wavy. He could give you the straight hair gene, along with your Mom. This means that two people with wavy hair could have children with straight hair, since the wavy genotype is Cs.
I hope I did not thoroughly confuse you,
Six kids, and the only one with somewhat wavy hair only has it in the back on the left side. (Never figure out if that little bounce at the back top of his right side was a wave or a cowlick. lol)
Also both parents were brown-haired. Mom had brown eyes. Dad has hazel. BUT, Dad had platinum blond as a baby, and had dark brown hair by the time he went to school. (His hair was so dark, he looked like it was black until he went outside. When he started going gray, he claimed he was just going back to blond again. lol) And Dad's second wife was a duplicate of Mom. (He married someone because she reminded him of Mom. BUT, she has a redheaded brother, and Mom's siblings all had brown hair too.)
Six kids from oldest to youngest:
Brown straight hair. Blue eyes.
Brown straight hair. Brown eyes. (Sometimes can catch hazel if he's outside and wearing the right color shirt.)
Brown straight hair. Brown eyes. (Me.)
Brown straight (except those two spots) hair. Brown eyes.
Blonde straight. Blue eyes.
Brown straight hair. Brown eyes.
Which is why I always thought straight hair was the dominant.
The one thing that is dominant in my family is Irish and German. Two countries known for straight hair. (Okay, Miri. Ruin that delusion too. lol)