AUSTIN -- State Rep. Charlie Geren, chairman of the House Administration Committee, sent a letter to his House colleagues Friday saying he will not accommodate a request by The Texas Tribune to release any of his federal income tax returns and reminding them that they are "under no legal obligation" to do so either."I will not be providing mine to them," Geren, R-Fort Worth, wrote in a letter to the other 149 members of the House. "It is up to you as an individual to make this choice."Geren's letter came the same day that the Tribune asked him for his last three returns, a request being made of all state lawmakers as part of a legislative transparency project. The Tribune recently began contacting lawmakers and has not received any returns. At least two lawmakers, including the vice chairwoman of Geren's committee, Donna Howard, D-Austin, have said they will turn theirs over.In a phone interview, Geren would not go into detail about his personal opposition to the Tribune's request, but said he thinks it's his "job to keep House members aware of what's going on.""I'm not going to give you mine. That's all I've got to say," he said. "It's none of your business what my income tax return looks like."Howard said in an interview that she took Geren's letter as a general factual memo, not as a warning. Still, she said, she plans to pass along her last three returns to the Tribune. State Rep. Elliott Naishtat, D-Austin, has also agreed to turn over his returns."I'm erring on the side of transparency," Howard said, "because I agree with some who would suggest that our personal financial disclosure forms are not very meaningful, and the [Texas] Ethics Commission has been criticized for not having much in the way of teeth."In Texas, lawmakers are required to submit a financial statement that lists their properties, stocks, bonds, mutual funds, gifts and sources of income, but not their net worth.Advocates of government transparency have long argued that full disclosure helps the electorate understand the motives and background of people running for public office.On the national stage, presidential candidate Mitt Romney has fielded intense criticism from opponents for refusing to share several years' worth of personal income tax returns. Democrats are using this to their advantage, suggesting that Romney, a wealthy businessman and former governor, may have something to hide.While trying to woo voters on the presidential trail, Gov. Rick Perry and his wife, Anita, released their 2010 income tax return in October. They have released previous tax returns as far back as 1987.In an interview with reporters last month, Perry said full disclosure is ideal: "No matter who you are or what office you are running for, you should be as transparent as you can be with your tax returns and other aspects of your life so that people have the appropriate ability to judge your background."Earlier this year, the four leading Republican contenders for retiring U.S. Sen. Kay Bailey Hutchison's seat released their federal income tax returns. It was practically a domino effect that started in January with former ESPN broadcaster Craig James' decision to release his last five tax returns. He called on his opponents to do the same. Within days, Lt. Gov. David Dewhurst, former Dallas Mayor Tom Leppert and former state Solicitor General Ted Cruz released their returns.James Henson, director of the Texas Politics Project at the University of Texas and a pollster for The Texas Tribune, said it often takes pressure from opponents for lawmakers to do more than the minimum: filling out the state financial disclosures.