The country now has one openly gay, one transsexual and two black MPs, which would have been unthinkable just a few years ago.
Recent surveys suggest more than half the population supports at least some sort of legal recognition for same-sex couples, if not marriage.
Conservatives are resisting the changing social attitudes all the more strongly for sensing that they are swimming against the tide. One issue that pits the Catholic Church against the majority of the people is in vitro fertilisation (IVF), a subject of intense debate in the Polish media.
The Vatican regards it as a sin because it splits sex from conception and because unused embryos will die.
Polish bishops famously described the practice as "refined abortion" and have threatened to excommunicate MPs who vote for anything other than to ban it.
Yet more than two thirds of Poles oppose any ban on IVF treatment.
And 85% of couples in the 25 to 30 age range told a recent study that they would consider using IVF if necessary.
In the absence of any legislation, IVF is legal in Poland - but it has to be done privately.
The people, and the European Union, have long been demanding a law that would regulate the use of the technique and allow the state health service to cover at least part of its costs.
Yet the ruling centre-right Civic Platform party, which routinely promises an IVF bill at election time, is a hostage to its conservative wing. A recent meeting of the party's parliamentary club at Jachranka, outside Warsaw, showed just how deep the split runs.
According to recordings obtained by Polish Newsweek, a weekly magazine, Donald Tusk, the prime minister, implicitly threatened to expel Jaroslaw Gowin, the justice minister, from the party if he didn't toe the line.
Mr Gowin is the author of the more conservative of two bills Civic Platform is considering. His proposal would limit IVF to married couples and outlaw the freezing of embryos, which makes the technique considerably more effective and cheaper.
While Mr Tusk bemoaned the lack of party unity ("What do we have in common, other than power?" he asked), Mr Gowin demanded that his bill be put forward as well as the more liberal variant - IVF available to all, refunded and including the freezing of embryos - proposed by Małgorzata Kidawa-Błońska.
The party's leadership hopes to find a compromise proposal to avoid the risk of a sizeable chunk of its members voting with the opposition.
The conservative Law and Justice party has called for prison sentences for doctors carrying out IVF procedures, but now says it could compromise - perhaps seeing a chance to capitalise on the split in Civic Platform.
At Jachranka though, party heavyweights on the conservative side, such as Hanna Gronkiewicz-Waltz, the mayor of Warsaw, joined Mr Gowin in indicating that they would not compromise.
John Godson, one of the two black MPs and a conservative though not a Catholic, dramatically threatened to quit the party if there were not a free vote on this issue. (He subsequently told our correspondent that he was actually leaning toward the more liberal option).
Their divergent views on freezing embryos means the two bills are practically irreconcilable. Mr Gowin now says it is unlikely any IVF legislation will pass in this parliament.
Krzystof Lukaszuk, a professor who heads the Invicta IVF clinics in Gdańsk and Warsaw, says that is no bad thing: regulation, he claims, would lead to red tape and delays that could reduce the chances of getting pregnant for many women.
IVF procedures are on average more successful in unregulated Poland than in the rest of Europe. They are also cheaper. For Professor Lukaszuk state refunding of IVF should not be an issue considering that the price Invicta offers, 13,000 złotys ($3,780), is a fraction of the resources that will subsequently be needed to bring up a child.
On the practical level, the situation is perhaps not as urgent as it is portrayed. Yet the fuss surrounding this issue - surely less controversial than that of civil partnerships for gays - hints at problems ahead for Civic Platform.
Inaction on IVF now means chalking up another item on the list of the government's unkept promises. For both conservative and liberal factions, that is a lesser evil than letting the issue break up the party.
But the rift is there, and if the stormier economic waters ahead sap Civic Platform's popularity, its cohesion could come under severe strain.