<?xml version="1.0"?><ownershipDocument>    <schemaVersion>X0101</schemaVersion><documentType>4</documentType><periodOfReport>2003-05-09</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>897075</issuerCik>        <issuerName>ZONAGEN INC</issuerName><issuerTradingSymbol>ZONA</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>1017832</rptOwnerCik>            <rptOwnerName>SUTTER MARTIN P</rptOwnerName>        </reportingOwnerId>        <reportingOwnerAddress>            <rptOwnerStreet1>  </rptOwnerStreet1>            <rptOwnerStreet2>  </rptOwnerStreet2>            <rptOwnerCity>  </rptOwnerCity>            <rptOwnerState>  </rptOwnerState>            <rptOwnerZipCode>  </rptOwnerZipCode>        </reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-05-09</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>633</value></transactionShares><transactionValue><value>1.58</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>184595</value><footnoteId id="F1" /></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeSecurity><footnotes><footnote id="F1">Includes 115,029 shares of Common Stock deemed to be beneficially owned by Mr. Sutter by virtue of his affiliation with Essex/Woodlands Health Ventures, L.P. and 524 shares held by certain of Mr. Sutter's family members.  Mr. Sutter disclaims beneficial ownership of the shares owned by Essex/Woodlands Health Ventures, L.P. and by his family members.</footnote></footnotes><ownerSignature><signatureName> /s/ Martin P. Sutter</signatureName><signatureDate>2003-05-13</signatureDate></ownerSignature></ownershipDocument>

