diff --git a/app/frontend/src/javascript/components/family-account/child-form.tsx b/app/frontend/src/javascript/components/family-account/child-form.tsx
index c65631d2c..02234f827 100644
--- a/app/frontend/src/javascript/components/family-account/child-form.tsx
+++ b/app/frontend/src/javascript/components/family-account/child-form.tsx
@@ -84,11 +84,12 @@ export const ChildForm: React.FC<ChildFormProps> = ({ child, onSubmit, supportin
         />
         <FormInput id="birthday"
           register={register}
-          rules={{ required: true, validate: (value) => moment(value).isBefore(moment().subtract(18, 'year')) }}
+          rules={{ required: true, validate: (value) => moment(value).isAfter(moment().subtract(18, 'year')) }}
           formState={formState}
           label={t('app.public.child_form.birthday')}
           type="date"
-          max={moment().subtract(18, 'year').format('YYYY-MM-DD')}
+          max={moment().format('YYYY-MM-DD')}
+          min={moment().subtract(18, 'year').format('YYYY-MM-DD')}
         />
         <FormInput id="phone"
           register={register}
diff --git a/app/frontend/src/javascript/components/form/form-input.tsx b/app/frontend/src/javascript/components/form/form-input.tsx
index b19d42ccc..5a1aed014 100644
--- a/app/frontend/src/javascript/components/form/form-input.tsx
+++ b/app/frontend/src/javascript/components/form/form-input.tsx
@@ -24,12 +24,13 @@ type FormInputProps<TFieldValues, TInputType> = FormComponent<TFieldValues> & Ab
   ariaLabel?: string,
   maxLength?: number,
   max?: number | string,
+  min?: number | string,
 }
 
 /**
  * This component is a template for an input component to use within React Hook Form
  */
-export const FormInput = <TFieldValues extends FieldValues, TInputType>({ id, register, label, tooltip, defaultValue, icon, className, rules, disabled, type, addOn, addOnAction, addOnClassName, addOnAriaLabel, placeholder, error, warning, formState, step, onChange, debounce, accept, nullable = false, ariaLabel, maxLength, max }: FormInputProps<TFieldValues, TInputType>) => {
+export const FormInput = <TFieldValues extends FieldValues, TInputType>({ id, register, label, tooltip, defaultValue, icon, className, rules, disabled, type, addOn, addOnAction, addOnClassName, addOnAriaLabel, placeholder, error, warning, formState, step, onChange, debounce, accept, nullable = false, ariaLabel, maxLength, max, min }: FormInputProps<TFieldValues, TInputType>) => {
   const [characterCount, setCharacterCount] = useState<number>(0);
 
   /**
@@ -102,7 +103,8 @@ export const FormInput = <TFieldValues extends FieldValues, TInputType>({ id, re
           placeholder={placeholder}
           accept={accept}
           maxLength={maxLength}
-          max={max} />
+          max={max}
+          min={min}/>
         {(type === 'file' && placeholder) && <span className='fab-button is-black file-placeholder'>{placeholder}</span>}
         {maxLength && <span className='countdown'>{characterCount} / {maxLength}</span>}
         {addOn && addOnAction && <button aria-label={addOnAriaLabel} type="button" onClick={addOnAction} className={`addon ${addOnClassName || ''} is-btn`}>{addOn}</button>}
diff --git a/app/models/child.rb b/app/models/child.rb
index 07c59c4c6..3d752ac54 100644
--- a/app/models/child.rb
+++ b/app/models/child.rb
@@ -15,7 +15,7 @@ class Child < ApplicationRecord
 
   # birthday should less than 18 years ago
   def validate_age
-    errors.add(:birthday, I18n.t('.errors.messages.birthday_less_than_18_years_ago')) if birthday.blank? || birthday > 18.years.ago
+    errors.add(:birthday, I18n.t('.errors.messages.birthday_less_than_18_years_ago')) if birthday.blank? || birthday < 18.years.ago
   end
 
   def full_name