The serious response :

"Liberals Like Christ" have two answers to that frequent query of "evangelical" Christians, a serious theological response, and a more down to earth, humorous response.
        The trouble with those who claim to be "born again" is that they don't even know what Jesus meant when he introduced the world to that expression.

in John's Gospel, Ch. 3: 3-21  

Jesus answered him, 'Very truly, I tell you, no one can see the kingdom of God without being born from above (or born again).'
        Nicodemus said to him, 'How can anyone be born after having grown old? Can one enter a second time into the mother's womb and be born?'
        Jesus answered, 'Very truly, I tell you, no one can enter the kingdom of God without being born of water and Spirit. What is born of the flesh is flesh, and what is born of the Spirit is spirit. Do not be astonished that I said to you, 'You must be born from above.' The wind blows where it chooses, and you hear the sound of it, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.'
        Nicodemus said to him, 'How can these things be?'
        Jesus answered him, 'Are you a teacher of Israel, and yet you do not understand these things? 'Very truly, I tell you, we speak of what we know and testify to what we have seen; yet you do not receive our testimony. If I have told you about earthly things and you do not believe, how can you believe if I tell you about heavenly things? No one has ascended into heaven except the one who descended from heaven, the Son of Man. And just as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, that whoever believes in him may have eternal life. For God so loved the world that he gave his only Son, so that everyone who believes in him may not perish but may have eternal life. 'Indeed, God did not send the Son into the world to condemn the world, but in order that the world might be saved through him. Those who believe in him are not condemned; but those who do not believe are condemned already, because they have not believed in the name of the only Son of God. And this is the judgment, that the light has come into the world, and people loved darkness rather than light because their deeds were evil. For all who do evil hate the light and do not come to the light, so that their deeds may not be exposed. But those who do what is true come to the light, so that it may be clearly seen that their deeds have been done in God.' "

{ in Matthew 7: 18-23 }  

"Thus you will know them by their fruits. Every tree that does not bear good fruit is cut down and thrown into the fire. not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only the one who does the will of my Father in heaven. On that day many will say to me, 'Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many deeds of power in your name?' Then I will declare to them, 'I never knew you; go away from me, you evildoers.' "

        And in the following important passage, Jesus warned that many who expect front row seats in heaven are in a big surprise, while many others will be surprised to be found so pleasing to Jesus and to God:

{ Matthew 25: 31-46 } 

When I, the Messiah, shall come in glory, and all the angels with me, then I shall sit upon my throne of glory.  And all the nations shall be gathered before me.  And I will separate the people as a shepherd separates the sheep from the goats, and place the sheep at my right hand, and the goats at my left.
        Then I, the King, shall say to those at my right,  "Come, blessed of my Father, into the Kingdom prepared for you from the founding of the world.  For I was hungry and you fed me; I was thirsty and you gave me water; I was a stranger and you invited me into your homes; naked and you clothed me; sick and in prison, and you visited me."
        Then these righteous ones will reply,  "Sir, when did we ever see you hungry and feed you?  Or thirsty and give you anything to drink?  Or a stranger, and help you?  Or naked, and clothe you?  When did we ever see you sick or in prison, and visit you?"  And I, the King, will tell them, "when you did it to these my brothers you were doing it to me!"
        Then I will turn to those on my left and say, "Away with you, you cursed ones, into the eternal fire prepared for the devil and his demons.  For I was hungry and you wouldn't feed me; thirsty, and you wouldn't give me anything to drink; a stranger, and you refused me hospitality; naked, and you wouldn't clothe me; sick, and in prison, and you didn't visit me."
        Then they will reply,  "Lord, when did we ever see you hungry or thirsty or a stranger or naked or sick or in prison, and not help you?"  And I will answer,  "When you refused to help the least of these my brothers, you were refusing help to me."  and they shall go away into eternal punishment; but the righteous into everlasting life."

Rejoice and be glad, for your reward is great in heaven,  for
in the same way they persecuted the prophets who went before you."

Here is the "Liberals Like Christ"
humorous response :

A young teacher explains to her class that she is a born-again Christian.  She asks which of the children are also born-again Christians.  Not really knowing what it means to be born-again, but wanting to be like their teacher, their hands explode into the air like fleshy fireworks.
        There is, however, one exception.  A girl named Sarah has not gone along with the crowd. The teacher asks her why she is not like the others.  "Because I'm not a Christian." "Then," asks the teacher, "what are you?" "I'm an atheist."
        The teacher is a little perturbed now, her face slightly red.  She asks Sarah why she is an atheist.  "It's just that my family isn't religious.  My Mom is atheist, and my Dad is atheist, so I am atheist."
        The teacher is now angry.  "That's no reason to be an atheist," she says loudly.  "What if your Mom was a moron, and your Dad was a moron.  What would you be then?"
        "Then," says Sarah, "I'd probably be a born-again Christian."

If you are a Christian offended by this fictional story, you are not alone.  But I hope it offends you for the same reason that it offends me.  What offends me is the attitude of the teacher, thinking that kids who are born into Christian families are better than children born into an un-Christian family.  When Jesus used the expression "unless one is born again", it had theological significance.  My guess is that he wouldn't appreciate the way his words have been bastardized by people who wouldn't know Jesus if they tripped over him.

The dogmatic (or orthodox) approach:

When dogmatic sheep bring a theological question to a dogmatic teacher, they don't want a laying out of the arguments on many sides, with a challenge to make a decision on their own.  They want "the right answer".  And once they get it, they're prepared to consider all the people who don't share their answer as wrong, (or unorthodox, heretical, lost, unsaved, etc.).