Bred in the bone. A part of one’s nature. “What’s bred in the bone will come out in the flesh.” A natural propensity cannot be repressed. Naturam furcâ expellas, autem usque redibit.

E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.

Nātūram expellās furcā, tamen usque recurret

Even if you drive Nature away with a pitchfork, she’ll still keep coming back

No matter how ferociously you drive Nature away, she’ll still keep coming back

The translations already provided seem more than adequate. Even so, here are alternatives intended to express the sense, more than the literal meaning, of the saying. Here are some justifications:
• expellās can have the sense of it is possible for you to drive away (but not you have the power or skill to drive away), but it can also have the sense of if you drive away, which seems more appealing here, especially in the presence of furcā and tamen
• furcā (with or using (a) pitchfork) suggests the great determination, intensity, ferocity, or even viciousness with which one might drive Nature away; in contemporary English, we might express this meaning with an expression such as at gunpoint
• tamen has a meaning like nevertheless, still, even so; it suggests that, here, furcā means even with a pitchfork
• usque adds a meaning like continuously, without stopping
• recurret is future tense: (she) will return or come back
I urge those who find fault with any of this to post explanations of my errors here. I’ll be very grateful.