Conjunge fratrem cum sorore
et propina illis poculum amoris
Conjoin (conjunge) brother with sister (fratrem cum sorore) and drink to their health (et propina illis) the cup of love (poculum amoris)!
For a hand-colored version, see Adam McLean's website: Emblem IV.
Non hominum foret in mundo nunc tanta propago,
Si fratri conjunx non data prima soror.
Ergo lubens conjunge duos ab utroque parente
Progenitos, ut sint foemina masque toro.
Praebibe nectareo Philothesia pocla liquore
Utrisque, et foetus spem generabit amor.
There would not be (non foret) now in the world (in mundo nunc) such a great stock of people (hominum tanta propago), if the first sister (si prima soror) had not been given to her brother (fratri non data) as a spouse (conjunx). Therefore (ergo) gladly conjoin (lubens conjunge) the two offspring (duos progenitos) from both parents (ab utroque parente) so that there may be (ut sint) female and male (foemina masque) for the marriage bed (toro). Offer to them both (praebibe utrisque) the cups of Philothesia (Philothesia pocla) with the nectar liquor (nectareo liquore), and love will product (generabit amor) hope of pregnancy (foetus spem).
This word Philothesia is not a classical Latin word, nor is it a Greek word, but it appears to be a slightly mistransliterated version of the Greek ἡ φιλοτησία (κύλιξ), philotesia, the friendship or loving cup that was part of the Greek symposiastic ritual (the "h" probably crept into the -thesia to make it seem more Greek). See, for example, Thomas Elyot's 16th-century dictionary which defines Philothesia as "a solemne feaste amonge the Grekes."
The commentary explains that this refers not to "brother and sister" in the sense of family relations, but instead the male and female of the human species. What most struck me was the last paragraph of the commentary which is in praise of medical interventions, interpreting the "pocula" in medical terms, as fertility treatments:
Quis enim ignorat humanum genus Medicinae plurimum debere, propterea, quod multae hominum myriades, eius beneficio et opera, nunc in mundo extent, qui non fuissent, nisi eorum parentes aut proavia vitio sterilitatis per remotionem causae et sublationem, seu impedimenti proximi et remoti, vindicati et liberati, aut ab abortu matres praeservatae forent?
Who indeed does not know (quis enim ignorat) that humankind (humanum genus) owes much to Medicine (Medicinae plurimum debere), and thus that (propterea quod) many myriads of people (multae hominum myriades) now exist in the world (nunc in mundo extent) by virtue of Medicine's benefits and work (eius beneficio et opera) who would not exist (qui non fuissent) if their parents or grandparents (eorum parentes aut proavia) had not been emancipated and freed (nisi vindicati et liberati) from the defect of sterility (vitio sterilitatis) by the removal and elimination of the cause (per remotionem causae et sublationem) or of the blockage, near or far (seu impedimenti proximi et remoti), or if their mothers (aut matres) had not been kept safe (praeservatae forent) from miscarriage (ab abortu).
And now for your listening pleasure:
Emblem I: Portavit eum ventus in ventre suo.
Emblem II: Nutrius ejus terra est.
Emblem III: Vade ad mulierem
Emblem IV: Conjunge fratrem cum sorore
Emblem XXXVI: Lapis projectus