Same-sex marriage, signed into law Thursday in Maryland, will bring significant changes to gay and lesbian couples here. But to their personal finances, maybe not so much.

"They are not going to see a huge immediate change in finances," says Mark Scurti, a Towson lawyer who specializes in counseling same-sex couples. The big difference, he says, will be in estate planning and the elimination of a hefty inheritance tax.

But those are state issues. The federal government doesn't recognize same-sex marriage, so these couples won't enjoy many of the benefits of straight couples. Most notably, gay spouses still won't be entitled to Social Security benefits based on a partner's work history.

The fate of same-sex marriage in Maryland, however, isn't settled. Opponents are expected to gather enough signatures to put the issue before voters in a November referendum. If this challenge fails, same-sex couples will be able to marry here next year.

In that case, here are some personal finance changes they could see after saying "I do":

Tax returns

Couples will be able to file a joint Maryland income tax return.

You'd think that would make tax preparation easier.

"It makes tax filing way more complicated," says Debra Neiman, a financial planner in Massachusetts, which passed same-sex marriage in 2004.

Because the U.S. government doesn't recognize these marriages, each partner will have to file a federal return. Maryland's return relies on information from the federal return, so couples will have to fill out a dummy federal return to know what to put down on their joint state return, Neiman says.

Filing separate federal returns, though, adds another complication. Married same-sex couples end up filing as single or head of household. And when they sign that return, they're declaring — "under penalties of perjury" — that all the information is true. A movement called Refuse to Lie encourages couples to tell the truth and file jointly.

Steven Weisman, a lawyer and senior lecturer at Bentley University in Massachusetts, recommends that his gay married clients add a cover letter to federal returns explaining that they are married under state law. This can help if the couple seeks a mortgage, he adds, because it shows that they are married and pooling their incomes.

Estate planning

With same-sex marriage, you can die without a will and your spouse will still be able to inherit some or all of your estate.

Maryland law determines how assets are distributed when people die without a will. If the deceased is married, the assets will be divided between the surviving spouse and children. And if there are no kids or parents, the surviving spouse will inherit everything.

"Now you will have someone who automatically has inheritance rights," Weisman says. "That's a big thing. Two-thirds of people don't have a will."

Same-sex spouses also will be able to postpone state taxes on estates that exceed $1 million when the first partner dies. Maryland allows each person to shelter up to $1 million from estate taxes, but spouses get an extra tax benefit. One spouse can leave an unlimited amount to the other, and that won't be subject to the estate tax until the second spouse dies.

And same-sex spouses will be able to avoid a pricey 10 percent inheritance tax in Maryland if one partner dies and leaves assets to the other, says Scurti, the Towson lawyer. Inherit from someone outside the family, and you will owe that tax.

(Maryland currently doesn't assess an inheritance tax on domestic partners who inherit a mate's share of a jointly owned primary residence. But, Scurti says, that's only if the couple executed a domestic partnership affidavit beforehand.)