Loop through products in the basket
    if prescription_required == yes
        set flag to yes
    end if
end loop

<?php
    $_product = Mage::getModel('catalog/product')->load($this->getData('product_id'));
    echo $_product->getName();
?>

// get your cart object
$quote = Mage::getSingleton('checkout/session')->getQuote();

foreach ($quote->getItems() as $item) {
    $productId = $item->getProductId();
    $product = Mage::getModel('catalog/product')->load($productId);
    $prescriptionRequired = $product->getAttributeText('prescription_required');

    // code for subscription handling goes here

}

<config>
    <!-- other code -->
    <global>
        <!-- other code -->
        <blocks>
            <checkout>
                <rewrite>
                    <agreements>Bartoszgorski_Conditionalagreements_Block_Agreements</agreements>
                </rewrite>
            </checkout>
        </blocks>
        <!-- other code -->
    </global>
</config>

public function getAgreements() {
    if(Mage::helper('conditionalagreements')->checkIfQuoteRequiresAgreements() == true) {
        return parent::getAgreements();
    } else {
        return array();
    }
}

<config>
    <!-- other code -->
    <global>
        <!-- other code -->
        <helpers>
            <conditionalagreements>
                <class>Bartoszgorski_Conditionalagreements_Helper</class>
            </conditionalagreements>
            <checkout>
                <rewrite>
                    <data>Bartoszgorski_Conditionalagreements_Helper_Data</data>
                </rewrite>
            </checkout>
        </helpers>
        <!-- other code -->
    </global>
</config>

public function getRequiredAgreementIds()
{
    if($this->checkIfQuoteRequiresAgreements() == true) {
        if (is_null($this->_agreements)) {
            if (!Mage::getStoreConfigFlag('checkout/options/enable_agreements')) {
                $this->_agreements = array();
            } else {
                $this->_agreements = Mage::getModel('checkout/agreement')->getCollection()
                    ->addStoreFilter(Mage::app()->getStore()->getId())
                    ->addFieldToFilter('is_active', 1)
                    ->getAllIds();
            }
        }
        return $this->_agreements;
    } else {
        return array();
    }
}

public function checkIfQuoteRequiresAgreements() {
    $showAgreements = false;
    $quote = Mage::getSingleton('checkout/session')->getQuote();
    foreach ($quote->getAllVisibleItems() as $quoteItem) {
        $product = Mage::getModel('catalog/product')->load($quoteItem->getProductId());
        if($product->getConditionalAgreements() == 1) {
            $showAgreements = true;
            break;
        }
    }
    return $showAgreements;
}