One of the most powerful secular groups in the US, the American Civil Liberties Union (ACLU), has filed a brief against Catholic adoption agencies in the US state of Illinois.

The group object to the policy of Catholic Charities, which administers Catholic adoption services in Illinois, of refusing to place children with same-sex couples. Catholic Charities are suing the state of Illinois to reinstate contracts which the state dropped on the basis of its policy regarding same-sex couples.

Under a new same-sex civil union law passed earlier this year, the state says that it can no longer fund charities which do not allowed homosexuals to be prospective adoptive parents.

The ACLU claim that the policy does “significant harm” to children in the custody of the Department of Children and Family Services (DCFS) and discriminates against same-sex couples who desire to act as foster or adoptive parents.

They are seeking to intervene in the case on the basis that children under the care of DCFS already are clients of the ACLU in a two-decade old federal lawsuit that is designed to improve conditions for children under the care of DCFS.

The ACLU’s filing on Friday noted that the law requires the State of Illinois to make all decisions with regard to children in DCFS care solely on the basis of the “best interests of the child” and not the religious beliefs of a private foster agency.

They reject Catholic Charities’ claim that it has a right to conscientiously object to State policy on the placement of children with same-sex parents.

Peter Breen, executive director of legal firm the Thomas More Society, and who is acting as counsel for Catholics Charities, said the organisation “has maintained the same policies for decades on the placement of children with unmarried couples.”

To assert that Catholic Charities is now suddenly not acting in the best interest of children means the civil liberties group was either “disingenuous or the ACLU has been asleep at the switch for the last 20 years,” he added.

In June, three Illinois Catholic dioceses sued the DCFS when the state agency chose not to renew its contracts with the various chapters of the faith-based adoption agency. Catholic Social Services-Diocese of Belleville also joined the lawsuit last month.

Catholic officials said that it informed the state about its religious objections before the June 1 enactment of the civil unions act and made two requests for a meeting with the state attorney general.

However, the requests were ignored, and adoption contracts were discontinued after the first without notice, according to the Thomas More Society.

The discontinued contracts pose a problem for the charities’ over 2,000 foster children. A local judge has temporarily halted the state-imposed disruption in the adoption/foster care contracts.

The trial is set to begin later this month.