(NEW YORK) -- A study from the Williams Institute, an LGBT think tank at the University of Los Angeles, estimates that about 25,000 transgender Americans could be disenfranchised in the upcoming election because of a patchwork of voter ID laws.
And it's not just voter ID requirements that are the problem.
Poll workers have discretion in giving voters a regular ballot or a provisional ballot, and bias could still affect who gets to vote. Provisional ballots can also be counted differently from regular ones.
Voter laws vary from state to state, but according to the Williams Institute study, voters will face the most complex requirements in Georgia, Indiana, Kansas, Mississippi, South Carolina, Pennsylvania, Tennessee, Texas and Wisconsin.
Four of those states -- Georgia, Kansas, Indiana and Tennessee -- have strict photo ID requirements in addition to laws that require sex reassignment surgery before birth certificates or licenses can be updated.
Studies on the transgender community have also found that they are more often than not economically disadvantaged and are more likely to change addresses or even be homeless, making it harder to register to vote.
When it's difficult to get ID -- for financial, medical or other reasons -- it's hard to cast a ballot, according to Mara Keisling, executive director of the National Center for Transgender Equality, which is on a mission to get transgender Americans to the polls. Some get so discouraged they stop trying.
Copyright 2012 ABC News Radio