Dave Birkin who played young Picard was the same kid who played old picard's nephew Rene, from Family.
1. Jean-Luc (possibly travelled through time and) screwed his sister-in-law Marie.
2. Robert stole/asked for Jean Luc's sperms because his spunk was rubbish.
3. Robert and Marie raised a clone of Jean-Luc because they were both barren.
4. Robert travelled through time and is his own father, as well as the father of Jean-Luc and Rene who may or may not be twins.
5. Rene was young Picard travelling though time fucking with his olderself.
6. 300 years ago during the Eugenics war, "a Picard who faught in the Eugenics War" cloned himself a thousand times, putting those tiny clusters of himself duplictaed, almost a perfect man, into stasis in a vault under Chateau Picard. Whenever the family line starts to waver, if a Picard cannot pull, they reach into the Vault for another clone and start all over again with the same 20th century specimens of sexy.
7. The Romulans replaced baby Rene in the hospital as a control to see if the clmour they generated Shinzon from was any good and could pass as a Picard?