is there any way to get rainbow person?

Usually luck or hard work (or perhaps a combination of both). I suggest you read the earlier posts in this thread.

I got my rainbow (female) when an adoption came up. I never turn an adoptee away and was glad when I adopted her. I have not had one since and she did not give me any rainbow kids waaaaaa!!

finally!
I had a rainbow girl, and saved the file in a backup, played it over and over. Get 3 marriage propsals in 1st half hour of game. That is 6 an hour. Over and over. Finally got a spike on 3rd propsal after 5 times. Resaved that one in backup file. They had a little gir1!
Yeah!

Dang!! I'm on my 8th generation, and no rainbow-haired peeps have been born to my families yet! Is there some way to make that happen?

I just got the bald guy 'cause I started a new family with him. The rainbow girl I got by marriage and there's no way to get the mohawk!

I noticed that there wasn't this particular girl on the chart: the one with the black-and-white striped hair. Where would she fall? Did I miss something?

She's 4th from the top on bigheads00.png (on the original image file).

does the guy have to have black spike hair???

i started my 4th family and just kept lookin for who to pick and i finally found him. it takes a while.