CHORUS: I say that mortals who have no experience
Of and have never had children
Have a better chance for happiness
Than those who bear them.

ΚΥΚΛΩΨ: καί φημι βροτῶν οἵτινές εἰσιν
πάμπαν ἄπειροι μηδ᾿ ἐφύτευσαν
παῖδας προφέρειν εἰς εὐτυχίαν
τῶν γειναμένων.

Euripides (485?-406? BC) Greek tragic dramatist

Medea [Μήδεια], l. 1090ff (431 BC) [tr. @sentantiq (2020)]
    (Source)

By missing out on the burden of how to rear children properly, and bequeathing them an adequate inheritance, all the while not knowing if the children will turn out to be good people or bad ones. Oh, yeah, and they might die prematurely.(Source (Greek)). Other translations:

I maintain,
They who in total inexperience live,
Nor ever have been Parents, are more happy
Than they to whom much progeny belongs.
[tr. Wodhull (1782)]

This truth to all will I declare,
The free, th' unwedded, those that claim
No title to a father's name,
Uncumber'd with that care,
The paths of life with purer pleasure trace,
Than those that own a numerous race,
Their inexperience yet untaught
Who have no child.
[tr. Potter (1814)]

And now I aver that of mortals those
Who have never wed, or known children theirs,
Than parents are happier far.
[tr. Webster (1868)]

And amongst mortals I do assert that they who are wholly without experience and have never had children far surpass in happiness those who are parents.
[tr. Coleridge (1891)]

And I say that those men who are entirely free from wedlock, and have not begotten children, surpass in happiness those who have families.
[tr. Buckley (1892)]

Now this I say — calm bliss, that ne'er
Knew love's wild fever of the blood,
The pains, the joys, of motherhood,
Passeth all parents' joy-blent care.
[tr. Way (Loeb) (1894)]

And thus my thought would speak: that she
Who ne'er hath borne a child nor known
Is nearer to felicity.
[tr. Murray (1906)]

This I say, that those who have never
Had children, who know nothing of it,
In happiness have the advantage
Over those who are parents.
[tr. Warner (1944)]

And this is my opinion: those men or women
Who never had children of their own at all
Enjoy the advantage in good fortune
Over those who are parents.
[tr. Vellacott (1963)]

My conclusion is that people
Who’ve never borne children
Are much happier
Than parents.
[tr. Podlecki (1989)]

I say that those mortals who are utterly without experience of children and have never borne them have the advantage in good fortune over those who have.
[tr. Kovacs (Loeb) (1994); tr. Kovacs / Zhang / Rogak]

And I declare that, in the matter of happiness, those mortals who have produced children are less fortunate than those who have no experience at all of parenthood.
[tr. Davie (1996)]

So I have this view that those who have no children, children that they have given birth to and have raised, those people are much happier than those who do have any!
[tr. Theodoridis (2004)]

I have come to believe that human beings who
have never had the experience of rearing
children, are much better off than
those of us who are parents.
[tr. Luschnig (2007)]

So I can claim that among human beings
those who have no experience of children,
who have never given birth to offspring,
such people have far more happiness
than those who have been parents.
[tr. Johnston (2008)]

And I say people who have no experience and no children are far more happy than those who have them.
[tr. Ewans (2022)]

I do declare that those among mortals who are wholly without experience of children’s birth far surpass in happiness those who are parents.
[tr. Coleridge / Ceragioli / Nagy / Hour25]