"You carry your child."
Translation:Tu portes ton enfant.
"Enfant" can be masculine or feminine. When the sex of the child is not important, the noun is assumed to be masculine, by default.
<T' > does not belong to "ton/ta" (possessive adjectives), but to "tu/te" (pronouns), example:"je t'écris" (I am writing to you)
When it comes to the possessive adjectives, when the following noun starts with a vowel, like "enfant", you use "ton" enfant, whichever the sex of the child. If the noun is feminine, like "eau", you also use "ton" to avoid the vowel hiatus : "ton eau".