Change.org, a petition website dedicated to empowering people to create social and political change, is extending its paid-leave program for new parents.

The company now will offer 18 weeks of fully-paid parental leave to every employee who becomes a new parent — biological or not. With 207 employees in 18 countries, Change.org’s team is 51% female and its leadership team is comprised of 40% women. The expanded program will become the most generous equal leave policy among all U.S. tech companies, says Change.org President and COO Jennifer Dulski.

“Our goal was to create a real parental leave program that supports all evolving families without creating financial hardship for them,” Dulski said in an interview with Fortune last night, while getting her 12-year-old daughter’s dinner ready. “We did a robust financial analysis and having a strong family policy is also good for business.”

Change.org’s announcement comes in the wake of news that Facebook FB and Apple AAPL now will pay for female employees to freeze their eggs. The perk will cover up to $20,000 in costs to allow women to extend their fertility and have more family-planning options. Some critics argued that the move is just a ploy to get female tech employees to work more years before having children, but infertility treatment is, in fact, a somewhat common benefit among big companies.

“Companies are working toward providing a set of benefits that are as flexible and generous as possible,” said Dulski, adding that Change.org has yet to include family planning options like egg freezing into its benefits package. “What you don’t want to do is create a set of policies that generate a set of behaviors that perpeturate inequalities among different types of parents.”

The petition website’s new policy is most similar to that of Facebook’s, which offers four months of paid leave to all parents, including same-sex couples and dads. At Yahoo YHOO , biological mothers get a total of 16 weeks of paid time off, whereas all other parents get eight weeks of paid leave. Google GOOG offers 18 weeks of paid leave to biological mothers while other new parents, regardless of gender, are given 12 weeks.

Yet these big tech firms are among a very select group of high-caliber employers that offer such generous parental leave packages. In 2012, only 11% of private industry workers had access to paid family leave, according to the Bureau of Labor Statistics, and the U.S. is one of just three countries in the world not to mandate paid leave. The lack of paid time off for many new parents in America is cited as a primary cause for the gender wage gap, as well as for the shortage of women in executive positions at big U.S. firms. The FAMILY Act, a proposal for paid family and medical leave, is making some progress in Congress and would provide up to 12 weeks of paid leave to qualifying workers for the birth or adoption of a new child.

“This is really the beginning,” Dulski said. “We are seeing a momentum both at the state and federal level. We think it is important to start with ourselves and our community We shouldn’t wait for legislation to take responsibility here and act.”

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