While federal law makes it illegal for a creditor to discriminate on the basis of race, color, religion, national origin, sex, marital status, age, or income received from an assistance program, there is no specific prohibition on discriminating in the granting of credit on the basis of sexual orientation. Under the law, if credit is denied, the applicant is entitled to a written explanation. In prohibiting discrimination on the basis of "sex," Congress meant to deal with whether a person is male or female, not sexual orientation.
Most lending institutions are concerned about the borrower's assets and ability to repay. Banks and credit unions would like to have more than one person liable for the account, so it should not be difficult for a gay or lesbian couple to obtain joint credit if they have sufficient resources. However, it is rarely a good idea for a same-sex couple to have a lot of joint credit, except for the mortgage and a small line of credit on a joint banking account. When credit is obtained jointly, the credit record of one partner affects that of the other. Many innocent people have had their credit ruined by the actions of a co-signer, so if you have an account with someone else, make sure the loan is always paid on time. Anyone who ends a relationship should call the bank or other institution to cancel all joint credit cards and other accounts. After you talk to the creditor, follow up with a letter. You will still be liable for debts up until that point, but you will not be liable for future advances obtained by the co-debtor.
For credit cards, an alternative to joint credit is to have the card issued in the name of the primary holder with a second card authorized for another person's use. The primary holder is responsible to the creditor for debts on the account. The person who is merely an authorized user probably cannot be held liable for the account, although a delinquency may show up on their credit report.