She testified that, there has never been a requirement that a couple produce children to have a valid marriage.
Cott's testimony highlighted the history and plight of freed slaves to marry, the struggles of interracial couples and the battle by women to retain personal property within a marriage.
Cott also highlighted that, "a woman lost her legal individuality. Jane Doe became Mrs. John Smith."
On cross examination, Prop 8 supporters took aim at Cott's credibility, trying to paint her as an, "advocate of same-sex marriage." The often tedious questioning covered Cott's lengthy body of work which dates back to the 1970s.
Prop 8 attorney David Thompson questioned her on issues of marriage that ranged from the puritans coming to America to the infidelity of former President Bill Clinton. Still, the attorneys for the sponsors of Prop 8 feel they damaged testimony of a key expert.
"In some respect, you might even say that the testimony became a disaster for the plaintiffs today," said Andy Pugno of Protect Marriage.
Jeff Zarrillo and Paul Katami are one of the couples who are plaintiffs. They say they are willing to be part of the case for one key reason.
"Marriage is our civil right and that being gay does not change our being Americans," said Katami. This trial is expected to last two to three weeks.