(Image courtesy Wikimedia Commons).

The progression of a marriage equality lawsuit to the U.S. Supreme Court will reach a significant milestone this month when, for the first time since landmark rulings last year, a federal appeals court will consider arguments on the issue of gay nuptials.

The U.S. Tenth Circuit Court of Appeals is set to hear oral arguments on April 10 in Denver in the case of Kitchen v. Herbert, the lawsuit that brought marriage equality briefly to the state of Utah, and will hear arguments April 17 in Bishop v. Smith, in which a lower court ruled Oklahoma’s ban on same-sex marriage is unconstitutional.

Doug NeJaime, a law professor at the University of California, Irvine, said he expects arguments from attorneys on behalf of same-sex couples during these arguments to focus on the impact of the states’ marriage bans on children.

“I expect we will see significant attention on the child centered rationales put forward by the state with responses regarding the detrimental impact on children raised by same-sex couples. Children are figuring prominently in these cases,” NeJaime said. “I also expect discussion about how Windsor affects the analysis of state bans on marriage.”

The harm to children raised by same-sex parents as a result of the Defense of Marriage Act was a significant factor in U.S. Associate Justice Anthony Kennedy’s decision last year against the ban. Numerous district courts have cited that language in their decisions striking down marriage bans.

The Tenth Circuit is one of five circuits where marriage equality cases are pending, but it’s hearing oral arguments sooner than the others following a decision to hear the litigation on an expedited basis.

Camilla Taylor, marriage director for Lambda Legal, said she’s optimistic both the Utah and Oklahoma cases are likely to succeed on the merits following the arguments.

“The briefing is extremely strong,” Taylor said. “There’s been a huge array of amicus briefs to go in. This will be the first oral argument in a federal circuit court, and so, of course it will be closely watched.”

Although the arguments mark the first time a federal appeals court has heard arguments on the marriage issue since the decisions against DOMA and California’s Proposition 8 last year, it’s not the first time ever a federal appeals court has heard arguments on whether a state can ban same-sex marriage. The U.S. Ninth Circuit Court of Appeals heard arguments in the case against Prop 8 in 2011 before striking down the amendment the following year.

The three-panel judge who’ll hear the marriage equality arguments in both cases consists of Judge Paul Kelly Jr., an appointee of President George H.W. Bush; Judge Carlos Lucero, a Clinton appointee; and Judge Jerome Holmes, an appointee of President George W. Bush.

Notably, Holmes was one of two judges that denied Utah’s request for a stay on same-sex marriages in Utah after a district court ruled the state’s marriage ban unconstitutional, but the U.S. Supreme Court stepped in to institute a stay.

Observers will likely be examining judges’ questions to make a prediction on the outcome of the ruling, though Lambda’s Taylor cautioned against placing too much emphasis on the line of questioning during the arguments.

“I think it’s always difficult to tell from oral arguments which way a court is likely to rule,” Taylor said. “I’m hoping folks won’t draw too many conclusions from which questions are asked because judges during oral arguments ask questions because they’re seeking the best formulated answer that they themselves wish to give in an opinion, so a question isn’t necessarily an indication of which way a court is likely to rule.”

Arguments in other appeals courts are somewhere down the line. The U.S. Fourth Circuit Court of Appeals, which is hearing the Virginia case, have set arguments for May 13. The appeals courts for the Fifth, Sixth and Ninth Circuits have not set a date as of Wednesday for arguments to hear the marriage equality issues.

According to the Human Rights Campaign, at least 55 marriage equality court cases are working their way through the courts across the country. These cases have been filed in 28 states — as well as Puerto Rico — and account for nearly 250 plaintiffs taking on state marriage bans.

As all of these cases make their way back to the Supreme Court, observers expect justices to take up one — if not all — of them during the year-long term beginning in fall 2014. That would likely mean a nationwide decision on marriage equality by the middle of 2015.