What does children mean in “Familiarity breeds contempt - and children.“? [closed]

Two thoughts are run together:

Familiarity breeds contempt {knowing people very well lets you see their faults}

Familiarity breeds children {physical familiarity between the sexes leads to children}

Hence

Familiarity breeds contempt and children.

A similar example of this particular way of playing with words (called Zeugma) is:

“You are free to execute your laws, and your citizens, as you see fit.”

For those whose first language is not English

What other answers have not explained so far is that the phrase "familiarity breeds contempt" is a very well known proverb in English that came about long before Mark Twain added the second part.

De Deo Socratis (On the God of Socrates)... This treatise ... contains a passage comparing gods and kings which is the first recorded occurrence of the proverb "familiarity breeds contempt": parit enim conversatio contemptum, raritas conciliat admirationem (familiarity breeds contempt, rarity brings admiration) https://en.wikipedia.org/wiki/Apuleius#Other_works

Of course, this could apply to many things, e.g. iron is common and people discard it easily whereas gold is rare and considered very valuable. Similarly it can be considered to apply to some relationships. Consider the high divorce rate in many countries.

Mark Twain simply used humour to add to the above. Familiarity also breeds children. It is a joke and is not intended for serious contemplation, nor does it have any great philosophical significance.

Consider it as follows

Mark Twain: "On the one hand, some people say that familiarity breeds contempt. However, on the other hand, in my experience, familiarity breeds children!" (everyone laughs)

The familiarity implies that too familiar can have the side-effect of children. It's meant to be humorous. How you feel about having children is up to you.