Ну, и немного о «маятнике Фуко»:

The earliest examples of the word otherwise are from Scottish, which suggests a Scandinavian origin, perhaps from a word akin to Norwegian dialectal fukka "copulate," or Swedish dialectal focka "copulate, strike, push," and fock "penis." Another theory traces it to Middle English fyke, fike "move restlessly, fidget," which also meant "dally, flirt," and probably is from a general North Sea Germanic word; compare Middle Dutch fokken, German fi cken "fu ck," earlier "make quick movements to and fro, flick," still earlier "itch, scratch;" the vulgar sense attested from 16c. This would parallel in sense the usual Middle English slang term for "have sexual intercourse," swive, from Old English swifan "to move lightly over, sweep" (see swivel). But OED remarks these "cannot be shown to be related" to the English word. Chronology and phonology rule out Shipley's attempt to derive it from Middle English firk "to press hard, beat."
Germanic words of similar form (f + vowel + consonant) and meaning 'copulate' are numerous. One of them is G. ficken. They often have additional senses, especially 'cheat,' but their basic meaning is 'move back and forth.' ... Most probably, fuck is a borrowing from Low German and has no cognates outside Germanic.
French foutre and Italian fottere look like the English word but are unrelated, derived rather from Latin futuere, which is perhaps from PIE root *bhau(t)- "knock, strike off," extended via a figurative use "from the sexual application of violent action"
http://www.etymonline.com/index.php?allowed_in_frame=0&search=fuck&searchmode=none .

Нас больше последняя фраза интересует:
Из латинского «futuere», которое, вероятно, произошло от PIE корня *bhau(t)- стучать, бить. Ну, не совсем так, это слово «пихаю». Замены «п» - «f» и «х» - «ck». В немецком еще и «т» (прописное m) – m – n.
Сравните нем. «ficken» с немецким «fichen» - пихта, сосна, по-английски «fir», видимо «с» - «<» - «r»

Клюге:
fichen., 'pine, fir,' from MidHG. vishte, f., OHG. fiohta, fiuhta, f., ' fir.' No cognate term is found in any of the other Teut. dialects, yet §ictote is proved from the non-Teut languages to be primitive ; comp. Gr. πεύκη, ' fir,' Lith. puszls, 'fir.' The HG. form is fuller by a dental affix than the Gr. and Lith. words.

Другой подход – пика, обратное от «копаю», или «колю», с заменой «л» - «п» - «р» - «pike».

1675:
To FUCK (foutre, F, futere, It. futico, L. φυτάω – сажать (растения); по одной версии происходят от “fuycke”, Belg. – укол или удар (кстати, “knock” – есть и в таком смысле); по другой – из нем. “Fuchen” – порождать. Ну, это вряд ли, скорее наоборот.

Интересно, что в «викторианскую» эпоху это слово уже «табу» (в английских этимологических словарях), ни в одном словаре 19 века его нет. Кстати, «табу» это русское «тайба» = тайна (Дьяченко).

1828:
FUTUO – из φυτεύω – сажать (растения). Ну, всяко бывает.

Дворецкий:
futuo, in, utum, ere совершать половой акт (f. aliquam Ctl, M).
fututio, onis f половой акт Ctl, M.
fututor, oris M nomen agentis futuo.

Льюс и Шорт:
fŭtŭo, ui, ūtum, 3, v. a. supine stem from root fu-, cf. Gr. φῖτυς, φιτόω, φυτεύω,
I to have connection with a female (rare), Cat. 97, 9; Mart. 10, 81, 1; 3, 87, 1.—Absol.: te futuente, Mart. 9, 3, 10.

Вероятно, это «е бать», замена «б» - «f». Это слово родственно «бить».
Собственно, британцы тоже так думают:
Futuō, infinitive futuere, perfect futuī, past participle futūtum, Latin for "to copulate", is richly attested and useful. Not only the word itself, but also derived words such as perfututum, which could be translated "totally fucked", and dēfutūta, "fucked out, exhausted from intercourse", are attested in Classical Latin literature. The derived noun futūtiō, "act of intercourse", also exists in Classical Latin, and the nomen agentis futūtor, corresponding to the English epithet "fucker", also derives from that word.
Etymology
Theories are:
• Akin to battuere, "to beat"; this metaphor has a long Indo-European heritage. Battuere itself may be a late borrowing from Germanic.
• Tucker's dictionary invites comparison with cōnfūtō, "suppress" or "beat down".
• From *fūtus (4th decl.), a verbal noun from root fu-, and originally may have referred to intercourse for procreation
http://en.wikipedia.org/wiki/Latin_profanity