Chandigarh: The Punjab and Haryana High Court has said that marriage between first cousins is illegal. The court said that marriage which the petitioner (man) wants to perform with a girl, who is his first cousin, was also per se illegal. “The submission in the present petition that as and when she (the girl) attains the age of 18 years, they will perform marriage is also per se illegal,” the judge said on Thursday while hearing the petition.