Let's speculate what the Ryder Family Mystery is, crackpot-theory style!

Alec Ryder is... afraid of mice and spiders. But oh so much greater is his fear that that the two species will cross-breed, to create an all-powerful race of mice-spiders who will immobilise human beings in giant webs to steal cheese.

*goes to his/her bedchamber*
*Smashes the door*
*DadRyder enters to the room*
Dad: What are you doing, you spoiled little brat?.
Ryder: What do you think?, i'm leaving!.
Dad: are you going with that Asari, what's her name?, Peewe?. You'll only get space AIDs with that punk!.
Ryder: Don't worry about that. I learned from the best... *point a Poster of Commander Shepard*

The twins are from the synthesis ending and are actually the biological children of EDI and Joker, EDI was bored one day and thought back about the Andromeda mission. She then extrapolated their chances of success and realized that they would fail and the only way they wouldn't is if they had two synthetic ubermensch grunts to fix everyone elses fuck ups so she modified her womb into a time machine and sent the twins to the only man she trusted, N7 Dad's husband - Scientist Dad, who also happens to be her creator and who she helped escape Cerberus and who then went on to work on the Andromeda project.

Jien Garson is mom Ryder, she's killed in an attack on the Nexus Vanguard before Alec et al get there on the Hyperion.

Alec goes cray upon finding out the Khett killed his betrothed, goes on guerilla warfare rampage with the angriest buggers on Nexus.

You and your twin will be pulled into this war on the Khett and will be either putting out fires or lighting them with dad across the Helios cluster.



Late in the game, you get drunk with Dad at a camp fire on Serrice Ice Brandy and recall the trial blazer your mom was: and how adventuring is in your blood and then, he reveals how his old best friend David Anderson could possibly be their real dad, since him and Jien had a crazy night on the red sand with him back in 2061..... awkward drunken threeway revelation makes Ryder twin 2 detonate a singularity, breaking the rest of the delicious Serrice Ice Brandy, tears ensue.

Alec Ryder is actually Mr. Krabs in disguise.

Alex Ryder IS the mother of the Ryder siblings. There father is actually Andromedan. Alec was kidnapped by a UFO and implanted while unconscious and returned to earth without knowing what had happened until he started showing signs of being pregnant and gave birth to twins nine months later. After piecing together what had happened, he vows to find a way to get to Andromeda to find his children's father... enlisting the help of a wealthy and crazy socialist... Jien Garson (who he falls in love with as they work on the project together).  The technology for getting to Andromeda was extracted from the genetic memory passed onto the Ryder children from their Andromedan father.

This...this is brilliant, it should be what is actually happening xD

Alec is actually a clone of bro Shepard from the from the future and the twins are actually the children of fem Shepard and Garrus from an alternate universe who clone Shepard agreed to look after. Alec's wife is the rachni queen (a third one) who escaped to Andromeda before the end of the rachni war (time travel). Alec created the reapers to track her down but the went insane and travelled back in time to destroy all organic life to prevent the rachni war. They tried to control the queen but it was the wrong one. Meanwhile Alec decides to search for his wife himself by travelling to Andromeda.

He's travelling to Andromeda to find a new ingredient for the krabby patty.

"We've slept for hundreds of years..." *cue woosh* "...but still our business at Krabby Patty is lacking."

"You're the new foodfinder!"

"This is... incredible!" *eats burger". "Now I know what makes you... special!"

FIGHT. FOR. A NEW. RECIPE.

Alec had it going with pride demon.

then spaces gangstas showed up shelling the place and the demon gave birth before dying.

Instead of sending his two space-mages-kids to the circle of the citadel, he sent them to andromeda, where lyrium is non-exsitant and templars are more tevinter-like

I want an answer to the question whether those 600 years happened both for inhabitants of the Milky Way and the crew of the Andromeda Expedition or...

...due to the sheer speed with which Andromeda Expedition was travelling at, the Einstein's theory of relativity did kick in somehow....

I think it should and while it was 600 years for the crew, it could have been millions of years for the Milky Way.
Well, in this case it would kinda give the new meaning to the "This is a one way trip" remark.

[UPDATE]

After a moment I realized, that this has to be the case.
Why would those 600 years have happened in the same pace for the Andromeda Initiative crew and the Milky Way?

This brings up another thing - did Milky Way races go extinct after so many millions of years or they eventually reached Type 3 civilization's capabilities in which case they should be able to traverse to Andromeda at the moment's notice... and gain contact with the Andromeda Initiative crew...

Eh.. I hope Mac Walters has good ideas on how to 'close' such issues sensitive for the consstency of the ME:A plot and introduced they right away in the game.

I believe I'm thinking too much about ME:A sometimes