In a word, yes. Tax matters that can be pretty simple for heterosexual couples can get quite complicated for gay and lesbian couples. For example, because the federal government doesn't recognize same-sex marriages, married same-sex couples in Massachusetts must file federal tax returns as "single" even though they can file a joint return in their home state. However, some couples may be able to claim their partner as a dependent on their return. To learn more, see Nolo's article Claiming an Unmarried Partner as a Dependent on Your Tax Return.
Same-sex married couples also don't qualify for the generous spousal exemptions from federal gift and estate tax, so these families must plan carefully to avoid or minimize tax liabilities. To learn more about tax issues, see Nolo's article Tax Issues for Same-Sex Couples.