Monday began as so many weeks do for the couple: helping their old dog off a bed too tall for him to scale on his own; watching their 4-year-old run laps around the newly finished kitchen; slowly stirring awake over cups of coffee and a long ride to work.

But there was something different this week. A feeling. A hope.

For the first time since Katie and Amy Evans-Reber wore out their finances — and emotions — trying to have a second child last year, there was a chance that, maybe, they could try again.

Gusto, the San Francisco human resources startup where Katie Evans-Reber works, on Monday became the first company in California to extend health coverage of fertility treatments to LGBT employees and their same-sex partners.

The company hopes it can lead by example and inspire other businesses, including those whose payroll and benefits Gusto manages, to do the same.

“A lot of the rules out there are a little bit antiquated because it’s just the way it’s been for a long time,” said Katie Evans-Reber, a member of Gusto’s internal human resources department who helped institute the new benefits package.

Gusto, which has 300 employees in San Francisco and Denver, also became the first midsize company — with 250 to 4,999 employees — to offer this benefit in the United States, according to Cigna, which provides insurance to Gusto employees.

Gusto did so by eliminating the need for a medical diagnosis of infertility for its employees to get fertility treatments covered. Fifteen states, including California, require employers to offer some fertility coverage. In practice, those benefits systematically exclude single women and same-sex couples because of how infertility is generally defined by health care providers and health insurance carriers.

Though same-sex couples are biologically incapable of conceiving a child together, to receive fertility benefits under most insurance policies, a doctor would have to find that a woman is clinically infertile, as defined by the American Society of Reproductive Medicine.

That definition: a woman who cannot conceive after 12 months of unprotected heterosexual intercourse.

Which, for Katie Evans-Reber and her wife Amy Evans-Reber, wasn’t going to happen.

Gusto’s fertility plan will initially cover about $20,000 worth of treatment. This includes the more common methods of intrauterine insemination and in vitro fertilization. It also covers gamete intrafallopian transfer and zygote intrafallopian transfer, less common surgical techniques thought to have greater rates of success.

Progressive family planning benefits have become something of a calling card for big-name tech companies throughout the Bay Area and Silicon Valley, all of which are battling to attract top talent and offer employees greater control over when — and how — they want to start a family.

Several companies offer generous family leave packages. Some provide on-site day care centers. Facebook and Apple made headlines two years ago when they announced they would cover the costs for female employees to freeze their eggs.

But none have yet to rework their plans to extend fertility treatment to all workers as Gusto has.

When trying to find a health benefits provider who would allow Gusto to alter its fertility package, regardless of sexual orientation, Gusto CEO Josh Reeves was shocked at how many had never even been asked the question before.

Cigna estimated that there are no more than four companies nationwide that offer employees similar benefits.

“These lofty benefits that you hear about at companies in the valley are typically referred to as perks,” Reeves said. “This is not a perk. This is a way to change lives.”

It goes without saying that having a child is even more challenging for men in same-sex relationships. The coverage Gusto offers, for instance, would not as of now extend to a woman who may be carrying a child for a gay male couple unless that woman also works at Gusto.

For men, sperm retrieval and short-term storage are covered by the new plan. But Reeves said he sees benefits as a work in progress and uses his own company to test new benefits that bridge the gap between “how things have been done” and “how things should be done.”

“None of this is finished,” he said. “Broadly speaking, I’d be proud if months or years from now we see this as one step in a journey.”

The benefit, which was announced at a company-wide meeting last month, may also be used by single women, who may not be clinically infertile, but want to have a child on their own.

Gusto’s benefits update also extended full coverage of sex reassignment surgery for transgender employees — a quality-of-life provision that Reeves said is consistent with the company’s values.

“It’s letting people know we have a space for them, a space where they can be their full authentic selves,” said Eric Obeng, who started an employee resource group for LGBT workers at Gusto. When he heard about the new benefits package, he said “I wanted to stand up and applaud. Yas queen, to the max.”

He wasn’t the only one. The company’s announcement was met with applause and tears — from employees, executives, Katie Evans-Reber and even her wife, Amy.

Amy Evans-Reber always knew she wanted to be a mother. She fantasized about having a little girl, but after five tries over 10 months of intrauterine insemination — which cost about $2,500 apiece — the couple found out Amy Evans-Reber was pregnant with a boy.

They named him Cash. Two years later, the women decided to try again. They wanted to try for a girl, to give Cash a sibling.

The treatments didn’t work on Amy Evans-Reber, who by then was in her late 30s. The couple turned to in vitro fertilization, but the girl they had hoped for, the girl they had already named, didn’t survive.

“We were so sure it was going to work, and when it didn’t,” Katie Evans-Reber’s voice trailed off. “I can’t tell you what that felt like.”

The toll was more than just emotional: The couple spent more than $40,000 trying to get pregnant a second time. They couldn’t afford to do another round.

On Monday, as the family sat down for dinner at the outside table surrounded by vegetables sown and grown with their own hands, Amy Evans-Reber wondered aloud about what it would have been like for them if they could have taken advantage of Gusto’s new fertility benefits.

“All of a sudden, the door doesn’t feel completely closed for us, when before this it did,” Amy Evans-Reber said. “Today we woke up and there’s a chance. There wasn’t a chance yesterday, but today. Today there is.”

Marissa Lang is a San Francisco Chronicle staff writer. Email: mlang@sfchronicle.com Twitter: @Marissa_Jae