I was born with strawberry blond hair, have red headed uncles and cousins, two of my siblings have copper speckled throughout their brown almost black hair. DH has red hair. He has two relatives with red hair. His grandpa and his step-cousin.
Because my hair has darkened to a lovely shade of whatever my hairstylist chooses, DH gets all the credit for our flock of red-heads. Really to see a family with FOUR red-headed children is quite the novelty. Grandma's at Costco come up and pet them.
I however can claim just as much influence in their hair color as he can. I know this now, but when I was pregnant with DD#1 we often wondered if we would get any red-headed babies. All four grandparents have dark brown hair. We are rockin' the recessive genes.
When DD#1 hair started to grow it was obviously red. Grandma's rejoiced.
When DD#2 arrived was imminent I emailed a geneticist about our chances of having another red-head.
His response was not what I expected, and I paraphrase.
I was told that Red hair (the hair, not the head it is on) is basically a freak of nature. It doesn't follow the same rules as other traits. Most people assume that it is simply Recessive, but it is not exclusively so. It is dominant to Blond. It also has the element of melanin to work its magic. People who carry the 'Dominant' Red hair gene can still be born with dark hair because the body carries high levels of melanin and it masks the red. This is why my siblings have copper shine to their hair, it is also why you see men with dark hair and red beards.
This is obviously a simplified explanation, but it sure helped me to understand how the red hair works. I no longer wonder if my baby will have red hair, I just assume that they will. Our track record is good (that sound is me knocking on wood). I love my flock of red headed children. And when they get petted in the produce section by an Alzheimer patient it presents a lovely teaching moment on having love and respect for others.