Who's your daddy?

Adults:
Celtic (left) and Germania (right)
Babies from left to right:
Austria, Prussia, Switzerland, Germany, (down row) France, Norway, Sweden, (upper row) Spain, North Italy, England


FACTS ARE CURRENTLY TO BE REVISED
A commenter claimed that most, if not all information that I used is wrong. As I mostly used german scientific books for these facts, I could indeed imagine that maybe other countries got to other results. I will look into that someday in the future and possibly rewrite the information here. Until then, read these facts with caution.
P.S.
Though I find it kind of funny, because in the end, no matter which scientist says what, the lesson that can be learned in the end is probably that nobody will ever know as it is just way too long ago to make any secure statement. So maybe also take it with a pinch of sarcasm

Some facts:
Despite common belief as well as several "ancestor stories", England does descend from Celtic as much as Germany does from Germania: namely not at all.
Celtic owned the land that was later inherited by Germany, Prussia, Austria, Switzerland and the northern parts of France (his upper body, which leans on Celtics leg). Historians are still discussing about the exact involvment of the Netherlands and Belgium, but couldn't completly agree or disagree with the theory that they might have been part of the celtic tribes that mainly covered north-west europe or if they had been independent (or even still been unsettled at that time).
Germania on the other side owned a lot more land, being Spain, South France (his lower body, which sits on Germanias foot), North Italy, but also nothern countries like England and the nordics (Norway and Sweden are absolutly sure, about the involvement of the others is a simliar discussion as about the Netherlands and Belgium).
The great trouble and reason for the later mix ups was, that both Celtic and Germania were very keen upon gaining more land by wandering around. They left traces in most countries of Europe and since they earned and lost land constantly, it is sometimes hard to pin down, if they had been residents or just short "visitors" to certain places. The countries above are only secured, because they actually contain at least a few permanent, 100% identified villages of the said ancestor.
Another, maybe random, fact is that England isn't "related" to Ireland and Scottland because of this. Ireland, Scottland and England had early been cultivated by people that had wandered there before Britain became a island (~7000 B.C.). When the germanics came (~4000 B.C.), they were able to repress the people back into the parts of Scottland and Ireland and overtake the now free land, making the people that live in England today having other ancestors then the people of Ireland and Scottland. Also, the fact that many people in Scottland and Ireland tend to belief that they have celtic ancestors is because Celtic came to that part of Britain around 4000 B.C. and cultivated the land beside them, mixing with them after some time (but they didn't, in the deeper sense, came to excistence through them).
I also made England obviously older then the baby countries.
That is because the germanic people that lived in England had trouble keeping up with the other tribes, due to Britain being a island and with having constant fights with scottish and irish tribes that kept them occupied. So England soon grew apart from the rest of Germania and they developed a variation of the original culture, that was simliar, but still independend. Meaning that England became a adult in this context a lot faster then the other countries that were raised by Germania and Celtic (and some even from Rome some time later) for a long time.

Soon after Rome gained power, it stole most of the countries from both Germania and Celtic. Even though he hadn't "raised" them, he educated them in his ways, enforcing his culture and language on them.
If Rome wouldn't have expanded like this, France, Spain and North Italy might also have developed a germanic language like Germany, England, Belgium, the Netherlands and most nordic countries. But with Romes powerful influence (which never completly reached north europe and thus leaved them mainly untouched with it's language except for the usage of latin by educated people), south europa and thus Spain, France and Italy, had soon succumbed and more or less forgot their original heritage.

Some more facts:
That Celtic looks desperatly at Germania has a reason, that also was reason to why many people belief to have germanic ancestors instead of celtic ones.
Back when both Celtic and Germania excisted next to each other, Germania was often stronger then Celtic. It happened more then just once that Germania was able to enslave celtic tribes. But Celtic wasn't stupid and took advantage of this situation, by learning from Germanias culture. In fact, Celtic and Germania became very simliar through this, with simliar culture, clothing and hair styles, language, the use of simliar runes, art, music, jewelery and more.
Germania teached Celtic in his ways and helped him with this in an amount that couldn't be greater, since Germania was one of the most advanced "primitive" cultures in the western world at that time.
The result was that most descendants (except for named Spain, France and Italy, which were "stolen" by Rome) have a very simliar language, featuring the germanic features of being hard and slightly aggressive sounding due to clear pronouncations in contrary to the more "flowing" languages that developed from the latin language (which is actually very interesting as well, since the common use of latin nowadays is a very clear pronouncation of latin [like it is typical for germanic languages], meaning that it might be possible that it had a totally different sound more close to the french and italian language back then).

Additional facts about England by Sims9287:
"In the British Isles we're all a mixed and confused cultural pot.
Genetically we have a very few traces of the early settlers who crossed the land bridge before it created the North Sea/English Channel. These are mostly found in isolated population in Scotland and the outer isles.
Then we have the Scandinavian influence in Scotland/N.Ireland and Northern England where you see a high percentage of tall red-head's. Then the Scottish/English border and Middle/Eastern England sees the Germanic influence with a higher prevalence of lanky blondes.
Then to the South of England you get the Norman influence which in itself was a mix of Celtic and Germanic.
Then to the far West of England & Wales / S.Ireland you have the Celtic influence where there's a high prevalence of darker Mediterranean features from the early Iberian settlers. Who are thought of as the 'Celts' of the British Isles and also account for the 'Black Irish' that you see today.
And then of course there's the Roman influence. Not a large genetic one but certainly a potent cultural presence.
The English language is a magpie language and the people aren't much different. They take bits and pieces from so many influences that it's impossible to accurately deconstruct them. Besides, as you said, when you look at Europe's history and take into account all the invasions and cultural mixing that went on, it's probably impossible to accurately deconstruct them too."

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Aaaaaaanyway, this leaves us with the most interesting fact, that Germany, DESPITE it's name directly hinting towards Germania, isn't really in any way related to it other then that germanic people had constantly attacked it's CELTIC ancestors.
Also, Britain - which tends to think of itself as being from Celtic - is in fact not celtic at all. The east part (England) is germanic and the west part was simply "visited" by celtics.
An even though france usually sees it's celtic roots, as the Gaul are a well-known tribe of Celtic from which most french came into excistence, it is only like this for NORTH France.

So I'm sorry, if I break any national pride by this, but I thought, this is interesting (and, honestly, both are so simliar that it can't be that horrible anyway, if they are mixed up xD).
And I wanted to make a cute family pic :3
(And I will probably never draw babies ever again, the faces of France and Sweden frustrate me even now...)

EDIT:
had made the correct assumption, that Switzerland was missing. I added him to Celtics babies, because he, like Austria, is confirmed to have had been settled by them (even though very late in comparison to the other countries). But he is a direct descendant of Celtic and thus belongs on his side.