You can buy Pelargonium graveolans seeds from several sources online. One page states (see link, https://pfaf.org/user/Plant.aspx?LatinName=Pelargonium+graveolens):

" Seed - best sown as soon as it is ripe in a greenhouse. Stored seed should be sown in early spring in a greenhouse. The seed germinates best with a minimum temperature of 13°c, germination usually taking place within 2 weeks though it sometimes takes some months[200]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for at least their first winter. If trying them outdoors, plant them out in early summer and consider giving them extra protection during the winter. Cuttings succeed at almost any time in the growing season but early summer is the best time in order for the new plant to become established before winter."

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5

Yes! it can be propagated by seeds despite stem cuttings:

do have a look on these pages:-

https://pfaf.org/user/Plant.aspx?LatinName=Pelargonium+graveolens

http://tropical.theferns.info/viewtropical.php?id=Pelargonium+graveolens

Thanks a lot.

Please take a look at these useful RG links.

Article Geranium Cultivation in India; Potentials &, Prospects.

Book "Rose scented geranium", a Pelargonium grown for the perfume industry