Is birth in a lowly family caused by sins in past life.?

That's what billions of Hindus have had drummed into them, as part of the caste system which keeps them serving the higher caste people. Jesus came to liberate us from such cruelty. Here's how the Bible explains things: "Now there were some present at that time who told Jesus about the Galileans whose blood Pilate had mixed with their sacrifices. Jesus answered, 'Do you think that these Galileans were worse sinners than all the other Galileans because they suffered this way?  I tell you, unless you repent, you too will all perish. Or those 18 who died when the tower in Siloam fell on them - do you think they were more guilty than all the others living in Jerusalem? I tell you, no! But unless you repent, you too will all perish."  Luke 13:1-5

The Bible clearly warns against this idea of reincarnation, saying "It is appointed unto man once to die, and after that to face judgment" Hebrews 9:27. Yet Jesus condescended to leave Heaven in the glory of the Godhead, to be born of a virgin in a very lowly family. He was born in a stable and so identified with sinful humanity that He became one of us, yet without sin. He chose to die to bear the punishment we all deserve for all our sins, so that all who trust in Him will be freely pardoned by God. Learn of Christ and know joy eternal. Get a Bible in your native language and start reading the gospel (good news) about just who Jesus is.

No, it's caused by sex.

there is no past life

Do not allow your mind to be swayed by ideas that sound interesting but do not have anything behind them.

When you go to see a magician, you don't go in thinking "magic is real", you go in thinking "magic isn't real, it's a bunch of clever tricks that are none-the-less very entertaining to watch". For some reason however, religious believers do not treat religious ideas the same way they treat magic acts: they see the beliefs as real, instead of just another clever concoction of thinking.

You are trying to answer questions for which the hunter-gatherer human brain is not evolved to answer.

Even nuclear quantum physicists and applied mathematicians studying the nature of reality can only understand mathematically, not visually about what's going on.

The matrix---by which I mean the environment we live in---cannot be understood objectively. Currently, there are no deterministic explanations for nature. Religions are in the same boat: they cannot offer any explanations except ones that aren't verifiable.

THERE IS NO PAST LIVES AND YOU ARE BORN WHERE U ARE BORN, IT HAS NOTHING TO DO WITH LOWLY OR HIGH FAMILY. U HAVE BELIEVED A LIE.

No!

Humility is a source of God's blessing to those who love him!

Births happen in all families of all classes.

Past lives are just fiction.

We all have one life and THIS is it.

No. Hope that clears things up for you.

Huh?  If you mean a birth the result of a conception taking place out of wedlock  then that could be said to have been a 'sin of the past' - something that took place 9 months earlier?  Resulting in an illigitimate child?

Probably not. Is there any evidence whatsoever that this might be the case? Any evidence whatsoever? Cultural or religious belief does not constitute evidence.