one’s own bodyСвоё is a reflexive possessive pronoun referring to the subject of the sentence. The phrase changes form according to case; for example, своего тела means “one’s own body” in the genitive case, while своё тело is the accusative form.
RU: Он учится принимать своё тело таким, какое оно есть.
EN: He is learning to accept his own body as it is.