Skandapurana 6.3.103.141

6.3.103.141

evaṃ putraṃ vinā saukhyaṃ martyaloke na vidyate .
vaṃśārthe maithunaṃ yasya svargārthe yasya bhāratī .. 103.141 ..

Thus without a son there is no happiness in the mortal world. / Intercourse is for progeny; speech is for the sake of heaven;